Experimental Skills — JEE Previous Year Questions

Every Experimental Skills question asked in JEE Main and JEE Advanced across the last 186 papers — 78 questions, each with its correct answer. Free to read, no account needed.

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All 78 Experimental Skills questions

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Q1·PhysicsNumericalJEE Advanced 2026

Two thin wires, Wire-1 of diameter 0.650 mm and Wire-2 of unknown diameter

d

are given. To obtain the value of

d

, the diameters of the two wires are measured with a screw gauge. The screw gauge has a pitch of 0.5 mm and there are 100 divisions on the circular scale (CS). The smallest division on the linear scale (LS) is 0.5 mm. The table shows the readings of LS and CS for the measurements. The value of

d

(in

\mu

m) is:

	LS (mm)	CS
Wire-1	0.5	42
Wire-2	1.5	95

Q2·PhysicsNumericalJEE Advanced 2026

As shown in the figure, the resistance of a galvanometer

G

can be found by the half-deflection method. Here the resistance

R_{2}

is adjusted such that when the key

K

is closed the deflection in the galvanometer becomes half of the value as compared to when

K

is open. Half-deflection is obtained at

R_{2} = 4

Ω and thus the galvanometer resistance is found to be 6 Ω. In this half-deflection condition the current (in mA) through the resistor

R_{1}

is:

Q3·PhysicsSingle correctJEE Main 2026

In a Vernier calipers, when both jaws touch each other, zero of the Vernier scale is shifted to the right of zero of the main scale and 7

^{\text{th}}

Vernier division coincides with a main scale reading. If the value of 1 main scale division is 1 mm and there are 10 Vernier scale divisions, then the Vernier caliper has

(A)0.07 cm negative zero error
(B)0.7 cm negative zero error
(C)0.07 cm positive zero error
(D)0.7 cm positive zero error

Q4·PhysicsSingle correctJEE Main 2026

In a screw gauge when the circular scale is given five complete rotations it moves linearly by 2.5 mm. If the circular scale has 100 divisions, the least count of screw gauge is _____ mm.

(A) $1 \times 10^{-2}$
(B) $1 \times 10^{-3}$
(C) $5 \times 10^{-2}$
(D) $5 \times 10^{-3}$

Q5·PhysicsSingle correctJEE Main 2026

In a screw gauge the zero of main scale reference line coincides with the fifth division of the circular scale when two studs are in contact. There are 100 divisions in circular scale and pitch of screw gauge is 0.1 mm. When diameter of a sphere is measured, the reading of main scale is 5 mm and

50^{\text{th}}

division of circular scale coincides with the reference line of main scale. The diameter of sphere is ______ mm.

(A)5.045
(B)5.055
(C)5.450
(D)5.550

Q6·PhysicsSingle correctJEE Main 2026

When both jaws of vernier callipers touch each other, zero mark of the vernier scale is right to zero mark of main scale,

4^{\text{th}}

mark on vernier scale coincides with certain mark on the main scale. While measuring the length of a cylinder, observer observes 15 divisions on main scale and

5^{\text{th}}

division of vernier scale coincides with a min scale division. Measured length of cylinder is ________ mm. (Least count of Vernier calliper = 0.1 mm)

(A)15.4
(B)15.1
(C)15.5
(D)15.9

Q7·PhysicsSingle correctJEE Main 2026

In an experiment, a set of reading are obtained –1.24 mm, 1.25 mm, 1.23 mm, 1.21 mm. The expected least count of the instrument used in recording these readings is _____mm.

(A)0.01
(B)0.001
(C)0.1
(D)0.05

Q8·PhysicsSingle correctJEE Main 2026

In a vernier callipers, 50 vernier scale divisions are equal to 48 main scale divisions. If one main scale division

= 0.05

mm, then the least count of the vernier callipers is ______ mm.

(A)0.002
(B)0.05
(C)0.02
(D)0.005

Q9·PhysicsSingle correctJEE Main 2026

In a screw gauge, the zero of the circular scale lies 3 divisions above the horizontal pitch line when their metallic studs are brought in contact. Using this instrument thickness of a sheet is measured. If pitch scale reading is 1 mm and the circular scale reading is 51 then the correct thickness of the sheet is ______ mm. [Assume least count is 0.01 mm]

(A) $1.50$
(B) $1.48$
(C) $1.54$
(D) $1.51$

Q10·PhysicsSingle correctJEE Main 2026

Using a simple pendulum experiment g is determined by measuring its time period T. Which of the following plots represent the correct relation between the pendulum length L and time period T ?

(A)(1)
(B)(2)
(C)(3)
(D)(4)

Q11·PhysicsSingle correctJEE Main 2026

In parallax method for the determination of focal length of a concave mirror, the object should always be placed :

(A)between the focus (F) and the centre of curvature (C) of the mirror ONLY
(B)at any point beyond the focus (F) of the mirror
(C)beyond the centre of the curvature (C) of the mirror ONLY
(D)between the pole (P) and the focus (F) of the concave mirror ONLY

Q12·PhysicsNumericalJEE Advanced 2025

A single slit diffraction experiment is performed to determine the slit width using the equation,

\frac{bd}{D} = m\lambda

, where b is the slit width, D the shortest distance between the slit and the screen, d the distance between the

m^{th}

diffraction maximum and the central maximum, and λ is the wavelength. D and d are measured with scales of least count of 1 cm and 1 mm, respectively. The values of λ and m are known precisely to be 600 nm and 3, respectively. The absolute error (in μm) in the value of b estimated using the diffraction maximum that occurs for m = 3 with d = 5 mm and D = 1 m is ______

Q13·PhysicsSingle correctJEE Advanced 2025

Figure 1 shows the configuration of main scale and Vernier scale before measurement. Fig. 2 shows the configuration corresponding to the measurement of diameter D of a tube. The measured value of D is:

(A)0.12 cm
(B)0.11 cm
(C)0.13 cm
(D)0.14 cm

Q14·PhysicsIntegerJEE Main 2025

The least count of a screw gauge is 0.01 mm. If the pitch is increased by 75% and number of divisions on the circular scale is reduced by 50%, the new least count will be _______

\times10^{-3}

mm.

Q15·PhysicsSingle correctJEE Main 2025

Given below are two statements. Statement I: In a vernier callipers, one vernier scale division is always smaller than one main scale division. Statement II: The vernier constant is given by one main scale division multiplied by the number of vernier scale divisions. In the light of the above statements, choose the correct answer:

(A)Both Statement I and Statement II are true
(B)Statement I is true but Statement II is false
(C)Both Statement I and Statement II are false
(D)Statement I is false but Statement II is true

Q16·PhysicsSingle correctJEE Main 2024

One main scale division of a vernier caliper is equal to

m

units. If

n^{th}

division of main scale coincides with

(n+1)^{th}

division of vernier scale, the least count of the vernier caliper is:

(A) $\frac{n}{(n+1)}$
(B) $\frac{m}{(n+1)}$
(C) $\frac{1}{(n+1)}$
(D) $\frac{m}{n(n+1)}$

Q17·PhysicsSingle correctJEE Main 2024

The diameter of a sphere is measured using a vernier caliper whose

9

divisions of main scale are equal to

10

divisions of vernier scale. The shortest division on the main scale is equal to

1\,mm

. The main scale reading is

2\,cm

and second division of vernier scale coincides with a division on main scale. If mass of the sphere is

8.635\,g

, the density of the sphere is:

(A) $2.5\,g/cm^3$
(B) $1.7\,g/cm^3$
(C) $2.2\,g/cm^3$
(D) $2.0\,g/cm^3$

Q18·PhysicsSingle correctJEE Main 2024

While measuring the diameter of a wire using a screw gauge the following readings were noted. Main scale reading is 1 mm and the 42nd division of the circular scale coincides with the reference line. Pitch of the screw gauge is 1 mm and it has 100 divisions on the circular scale. The diameter of the wire is

\tfrac{x}{50}

mm. The value of

x

is:

(A) $142$
(B) $71$
(C) $42$
(D) $21$

Q19·PhysicsSingle correctJEE Main 2024

In a vernier calliper, when both jaws touch each other, zero of the vernier scale shifts towards left and its

4^{th}

division coincides exactly with a certain division on main scale. If 50 vernier scale divisions equal to 49 main scale divisions and zero error in the instrument is

0.04

mm then how many main scale divisions are there in 1 cm ?

(A)40
(B)5
(C)20
(D)10

Q20·PhysicsSingle correctJEE Main 2024

In finding out refractive index of glass slab the following observations were made through travelling microscope 50 vernier scale division = 49 MSD; 20 divisions on main scale in each cm For mark on paper MSR = 8.45 cm, VC = 26 For mark on paper seen through slab MSR = 7.12 cm, VC = 41 For powder particle on the top surface of the glass slab MSR = 4.05 cm, VC = 1 (MSR = Main Scale Reading, VC = Vernier Coincidence) Refractive index of the glass slab is :

(A)1.42
(B)1.52
(C)1.24
(D)1.35

Q21·PhysicsNumericalJEE Main 2024

In the experiment to determine the galvanometer resistance by the half-deflection method, the plot of

\dfrac{1}{\theta}

versus the resistance R of the resistance box is shown in the figure. The figure of merit of the galvanometer is ___

\times10^{-1}

A/division. [The source has emf 2 V.]

Q22·PhysicsSingle correctJEE Main 2024

Time periods of oscillation of the same simple pendulum measured using four different measuring clocks were recorded as 4.62 s, 4.632 s, 4.6 s and 4.64 s. The arithmetic mean of these readings to the correct significant figures is:

(A)4.623 s
(B)4.62 s
(C)4.6 s
(D)5 s

Q23·PhysicsSingle correctJEE Main 2024

A vernier callipers has 20 divisions on the vernier scale, which coincide with the 19th division on the main scale. The least count of the instrument is 0.1 mm. One main scale division is equal to __________ mm.

(A)1
(B)0.5
(C)2
(D)5

Q24·PhysicsSingle correctJEE Main 2024

In an experiment to measure the focal length

(f)

of a convex lens, the least count of the measuring scales for the position of object

(u)

and for the position of image

(v)

are

\Delta u

and

\Delta v

, respectively. The error in the measurement of the focal length of the convex lens is:

(A) $f^2\left(\dfrac{\Delta u}{u}+\dfrac{\Delta v}{v}\right)$
(B) $f^2\left(\dfrac{\Delta u}{u^2}+\dfrac{\Delta v}{v^2}\right)$
(C) $2f\left(\dfrac{\Delta u}{u}+\dfrac{\Delta v}{v}\right)$
(D) $f\left(\dfrac{\Delta u}{u}+\dfrac{\Delta v}{v}\right)$

Q25·PhysicsSingle correctJEE Main 2024

To measure the temperature coefficient of resistivity

\alpha

of a semiconductor, an electrical arrangement shown in the figure is prepared. The arm BC is made up of the semiconductor. The experiment is being conducted at

25^{\circ}

C and resistance of the semiconductor arm is 3 m

\Omega

. Arm BC is cooled at a constant rate of

2^{\circ}

C/s. If the galvanometer G shows no deflection after 10 s, then

\alpha

is:

(A) $-2\times 10^{-2}\,^{\circ}$ C $^{-1}$
(B) $-1.5\times 10^{-2}\,^{\circ}$ C $^{-1}$
(C) $-1\times 10^{-2}\,^{\circ}$ C $^{-1}$
(D) $-2.5\times 10^{-2}\,^{\circ}$ C $^{-1}$

Q26·PhysicsSingle correctJEE Main 2024

10

divisions on the main scale of a Vernier calliper coincide with

11

divisions on the Vernier scale. If each division on the main scale is of

5

units, then the least count of the instrument is:

(A) $\dfrac12$
(B) $\dfrac{10}{11}$
(C) $\dfrac{50}{11}$
(D) $\dfrac{5}{11}$

Q27·PhysicsSingle correctJEE Main 2024

If 50 Vernier divisions are equal to 49 main scale divisions of a travelling microscope and one smallest reading of main scale is 0.5 mm, the Vernier constant of travelling microscope is:

(A)0.1 mm
(B)0.1 cm
(C)0.01 cm
(D)0.01 mm

Q28·PhysicsSingle correctJEE Main 2024

Identify the physical quantity that cannot be measured using spherometer:

(A)Radius of curvature of concave surface
(B)Specific rotation of liquids
(C)Thickness of thin plates
(D)Radius of curvature of convex surface

Q29·PhysicsSingle correctJEE Main 2024

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : In Vernier calliper if positive zero error exists, then while taking measurements, the reading taken will be more than the actual reading. Reason (R) : The zero error in Vernier Calliper might have happened due to manufacturing defect or due to rough handling. In the light of the above statements, choose the correct answer from the options given below :

(A)Both (A) and (R) are correct and (R) is the correct explanation of (A)
(B)Both (A) and (R) are correct but (R) is not the correct explanation of (A)
(C)(A) is true but (R) is false
(D)(A) is false but (R) is true

Q30·PhysicsSingle correctJEE Main 2023

A body of mass

(5\pm 0.5)\,kg

is moving with a velocity of

(20\pm 0.4)\,m/s

. Its kinetic energy will be:

(A) $(1000\pm 140)\,J$
(B) $(1000\pm 0.14)\,J$
(C) $(500\pm 0.14)\,J$
(D) $(500\pm 140)\,J$

Q31·PhysicsSingle correctJEE Main 2023

Two resistances are given as

R_1=(10\pm 0.5)\,\Omega

and

R_2=(15\pm 0.5)\,\Omega

. The percentage error in the measurement of equivalent resistance when they are connected in parallel is:

(A) $6.33$
(B) $2.33$
(C) $4.33$
(D) $5.33$

Q32·PhysicsSingle correctJEE Main 2023

A 2 metre long scale with least count of 0.2 cm is used to measure the locations of objects on an optical bench. While measuring the focal length of a convex lens, the object pin and the convex lens are placed at 80 cm mark and 1 m mark, respectively. The image of the object pin on the other side of lens coincides with image pin that is kept at 180 cm mark. The percentage error in the estimation of focal length is:

(A) $1.02$
(B) $0.85$
(C) $1.70$
(D) $0.51$

Q33·PhysicsSingle correctJEE Main 2023

A student is provided with a variable voltage source

V

, a test resistor

R_T=10\,\Omega

, two identical galvanometers

G_1

and

G_2

and two additional resistors,

R_1 = 10\,M\Omega

and

R_2 = 0.001\,\Omega

. For conducting an experiment to verify Ohm's law, the most suitable circuit is:

(A)(1)
(B)(2)
(C)(3)
(D)(4)

Q34·PhysicsNumericalJEE Main 2023

In a screw gauge, there are

100

divisions on the circular scale and the main scale moves by

0.5

mm on a complete rotation of the circular scale. The zero of circular scale lies

6

divisions below the line of graduation when two studs are brought in contact with each other. When a wire is placed between the studs,

4

linear scale divisions are clearly visible while

46^{th}

division the circular scale coincide with the reference line. The diameter of the wire is _________

\times10^{-2}

Q35·PhysicsNumericalJEE Main 2023

In an experiment for estimating the value of focal length of converging mirror, image of an object placed at

40

cm from the pole of the mirror is formed at distance

120

cm from the pole of the mirror. These distances are measured with a modified scale in which there are

20

small divisions in

1

cm. The value of error in measurement of focal length of the mirror is

\dfrac{1}{K}

cm. The value of K is

Q36·PhysicsNumericalJEE Main 2023

In an experiment of measuring the refractive index of a glass slab using travelling microscope in physics lab, a student measures real thickness of the glass slab as

5.25\,mm

and apparent thickness of the glass slab as

5.00\,mm

. Travelling microscope has

20

divisions in one cm on main scale and

50

divisions on vernier scale is equal to

49

divisions on main scale. The estimated uncertainty in the measurement of refractive index of the slab is

\dfrac{x}{10}\times10^{-3}

, where

x

is _____.

Q37·PhysicsSingle correctJEE Main 2022

In an experiment to find out the diameter of wire using screw gauge, the following observation were noted : (a) Screw moves 0.5 mm on main scale in one complete rotation (b) Total divisions on circular scale = 50 (c) Main scale reading is 2.5 mm (d)

45^{th}

division of circular scale is in the pitch line (e) Instrument has 0.03 mm negative error Then the diameter of wire is :

(A)2.92 mm
(B)2.54 mm
(C)2.98 mm
(D)3.45 mm

Q38·PhysicsSingle correctJEE Main 2022

A travelling microscope has 20 divisions per cm on the main scale while its Vernier scale has total 50 divisions and 25 Vernier scale divisions are equal to 24 main scale divisions, what is the least count of the travelling microscope ?

(A)0.001 cm
(B)0.002 mm
(C)0.002 cm
(D)0.005 cm

Q39·PhysicsNumericalJEE Main 2022

The one division of main scale of vernier callipers reads 1 mm and 10 divisions of Vernier scale is equal to the 9 divisions on main scale. When the two jaws of the instrument touch each other the zero of the Vernier lies to the right of zero of the main scale and its fourth division coincides with a main scale division. When a spherical bob is tightly placed between the two jaws, the zero of the Vernier scale lies in between 4.1 cm and 4.2 cm and

6^{\text{th}}

Vernier division coincides with a main scale division. The diameter of the bob will be______

10^{-2}

Q40·PhysicsSingle correctJEE Main 2022

A screw gauge of pitch 0.5mm is used to measure the diameter of uniform wire of length 6.8cm, the main scale reading is 1.5 mm and circular scale reading is 7. The calculated curved surface area of wire to appropriate significant figures is : [Screw gauge has 50 divisions on the circular scale]

(A)6.8cm $^{2}$
(B)3.4cm $^{2}$
(C)3.9cm $^{2}$
(D)2.4cm $^{2}$

Q41·PhysicsSingle correctJEE Main 2022

In a Vernier Calipers. 10 divisions of Vernier scale is equal to the 9 divisions of main scale. When both jaws of Vernier calipers touch each other, the zero of the Vernier scale is shifted to the left of zero of the main scale and

4^{\text{th}}

Vernier scale division exactly coincides with the main scale reading. One main scale division is equal to 1 mm. While measuring diameter of a spherical body, the body is held between two jaws. It is now observed that zero of the Vernier scale lies between 30 and 31 divisions of main scale reading and

6^{\text{th}}

Vernier scale division exactly. coincides with the main scale reading. The diameter of the spherical body will be :

(A)3.02 cm
(B)3.06 cm
(C)3.10 cm
(D)3.20 cm

Q42·PhysicsNumericalJEE Main 2022

The vernier constant of Vernier callipers is 0.1 mm and it has zero error of (–0.05) cm. While measuring diameter of a sphere, the main scale reading is 1.7 cm and coinciding vernier division is 5. The corrected diameter will be______

\times 10^{-2}

cm.

Q43·PhysicsSingle correctJEE Main 2022

For using a multimeter to identify diode from electrical components. choose the correct statement out of the following about the diode :

(A)It is two terminal device which conducts current in both directions.
(B)It is two terminal device which conducts current in one direction only
(C)It does not conduct current gives an initial deflection which decays to zero.
(D)It is three terminal device which conducts current in ne direction only between central terminal and either of the remaining two terminals

Q44·PhysicsNumericalJEE Main 2022

In a vernier callipers, each cm on the main scale is divided into 20 equal parts. If tenth vernier scale division coincides with nineth main scale division. Then the value of vernier constant will be .............. ×

10^{-2}

mm.

Q45·PhysicsNumericalJEE Main 2022

A travelling microscope is used to determine the refractive index of a glass slab. If 40 divisions are there in 1 cm on main scale and 50 Vernier scale divisions are equal to 49 main scale divisions, then least count of the travelling microscope is ______×

10^{-6}

Q46·PhysicsSingle correctJEE Main 2022

If n represents the actual number of deflections in a converted galvanometer of resistance G and shunt resistance S. Then the total current I when its figure of merit is K will be :

(A) $\frac{KS}{\left(S+G\right)}$
(B) $\frac{\left(G+S\right)}{nKS}$
(C) $\frac{nKS}{\left(G+S\right)}$
(D) $\frac{nK\left(G+S\right)}{S}$

Q47·PhysicsSingle correctJEE Main 2022

A teacher in his physics laboratory allotted an experiment to determine the resistance (G) of a galvanometer. Students took the observations for

\frac{1}{3}

deflection in the galvanometer. Which of the below is true for measuring value of G?

(A) $\frac{1}{3}$ deflection method cannot be used for determining the resistance of the galvanometer.
(B) $\frac{1}{3}$ deflection method can be used and in this case the G equals to twice the value of shunt resistance(s).
(C) $\frac{1}{3}$ deflection method can be used and in this case, the G equals to three times the value of shunt resistance(s)
(D) $\frac{1}{3}$ deflection method can be used and in this case the G value equals to the shunt resistance(s).

Q48·PhysicsSingle correctJEE Advanced 2021

The smallest division on the main scale of a Vernier calipers is 0.1 cm. Ten divisions of the Vernier scale correspond to nine divisions of the main scale. The figure below on the left shows the reading of this calipers with no gap between its two jaws. The figure on the right shows the reading with a solid sphere held between the jaws. The correct diameter of the sphere is

(A)3.07 cm
(B)3.11 cm
(C)3.15 cm
(D)3.17 cm

Q49·PhysicsNumericalJEE Main 2021

The diameter of a spherical bob is measured using a vernier callipers. 9 divisions of the main scale, in the vernier callipers, are equal to 10 divisions of vernier scale. One main scale division is 1 mm. The main scale reading is 10 mm and 8

^{th}

division of vernier scale was found to coincide exactly with one of the main scale division. If the given vernier callipers has positive zero error of 0.04 cm, then the radius of the bob is______

\times

^{-2}

cm.

Q50·PhysicsSingle correctJEE Main 2021

In a Screw Gauge, fifth division of the circular scale coincides with the reference line when the ratchet is closed. There are 50 divisions on the circular scale, and the main scale moves by 0.5 mm on a complete rotation. For a particular observation the reading on the main scale is 5 mm and the

20^{th}

division of the circular scale coincides with reference line. Calculate the true reading.

(A)5.00 mm
(B)5.25 mm
(C)5.15 mm
(D)5.20 mm

Q51·PhysicsSingle correctJEE Main 2021

Assertion A : If in five complete rotations of the circular scale, the distance travelled on main scale of the screw gauge is 5 mm and there are 50 total divisions on circular scale, then least count is 0.001 cm. Reason R : Least Count =

\frac{\text{Pitch}}{\text{Total divisions on circular scle}}

In the light of the above statement, choose the most appropriate answer from the options given below :

(A)A is correct but R is not correct.
(B)A is not correct but R is correct.
(C)Both A and R are correct and R is NOT the correct explanation of A .
(D)Both A and R are correct and R is the correct explanation of A .

Q52·PhysicsNumericalJEE Main 2021

Student A and Student B used two screw gauges of equal pitch and 100 equal circular divisions to measure the radius of a given wire. The actual value of the radius of the wire is 0.322 cm. The absolute value of the difference between the final circular scale readings observed by the students A and B is ____________. [Figure shows position of reference 'O' when jaws of screw gauge are closed ] Given pitch = 0.1 cm.

Q53·PhysicsSingle correctJEE Main 2021

Choose the correct option :

(A)True dip is not mathematically related to apparent dip.
(B)True dip is always greater than the apparent dip.
(C)True dip is always equal to apparent dip.
(D)True dip is less than the apparent dip.

Q54·PhysicsNumericalJEE Main 2021

Three students

S_1, S_2

and

S_3

perform an experiment for determining the acceleration due to gravity (g) using a simple pendulum. They use different lengths of pendulum and record time for different number of oscillations. The observations are as shown in the table. Student No. | Length of Pendulum (cm) | No. of oscillations (n) | Total for n oscillations | Time period (s) 1 | 64.0 | 8 | 128.0 | 16.0 2 | 64.0 | 4 | 64.0 | 16.0 3 | 20.0 | 4 | 36.0 | 9.0 (Least count of length = 0.1 cm least count for time = 0.1 s) If

E_1

E_2

and

E_3

are the percentage errors 'g' for students 1, 2 and 3 respectively, then the minimum percentage error is obtained by student no. ________.

Q55·PhysicsSingle correctJEE Main 2021

In the experiment of Ohm's law, a potential difference of 5.0 V is applied across the end of a conductor of length 10.0 cm and diameter of 5.00 mm. The measured current in the conductor is 2.00 A. The maximum permissible percentage error in the resistivity of the conductor is :-

(A)3.9
(B)8.4
(C)7.5
(D)3.0

Q56·PhysicsSingle correctJEE Main 2021

The vernier scale used for measurement has a positive zero error of 0.2 mm. If while taking a measurement it was noted that '0' on the vernier scale lies between 8.5 cm and 8.6 cm, vernier coincidence is 6, then the correct value of measurement is_____ cm. (least count = 0.01 cm)

(A)8.36 cm
(B)8.54 cm
(C)8.58 cm
(D)8.56 cm

Q57·PhysicsSingle correctJEE Main 2021

One main scale division of a vernier callipers is 'a' cm and n

^{th}

division of the vernier scale coincide with (n − 1)

^{th}

division of the main scale. The least count of the callipers in mm is :

(A) $\frac{10na}{(n-1)}$
(B) $\frac{10a}{(n-1)}$
(C) $\left(\frac{n-1}{10n}\right)a$
(D) $\frac{10a}{n}$

Q58·PhysicsSingle correctJEE Main 2021

The pitch of the screw guage is 1 mm and there are 100 divisions on the circular scale. When nothing is put in between the jaws, the zero of the circular scale lines 8 divisions below the reference line. When a wire is placed between the jaws, the first linear scale division is clearly visible while

72^{nd}

division on circular scale coincides with the reference line. The radius of the wire is :

(A)1.64 mm
(B)1.80 mm
(C)0.82 mm
(D)0.90 mm

Q59·PhysicsSingle correctJEE Main 2020

A screw gauge has 50 divisions on its circular scale. The circular scale is 4 units ahead of the pitch scale marking, prior to use. Upon one complete rotation of the circular scale, a displacement of 0.5 mm is noticed on the pitch scale. The nature of zero error involved, and the least count of the screw gauge, are respectively:

(A)Negative, 2 μm
(B)Positive, 10 μm
(C)Positive, 0.1 mm
(D)Positive, 0.1 μm

Q60·PhysicsSingle correctJEE Main 2020

A circuit to verify Ohm's law uses ammeter and voltmeter in series or parallel connected correctly to the resistor. In the circuit:

(A)ammeter is always used in parallel and voltmeter is series.
(B)both ammeter and voltmeter must be connected in parallel.
(C)ammeter is always connected in series and voltmeter in parallel.
(D)both, ammeter and voltmeter must be connected in series.

Q61·PhysicsSingle correctJEE Main 2020

A galvanometer is used in laboratory for detecting the null point in electrical experiments. If, on passing a current of 6 mA it produces a deflection of 2°, its figure of merit is close to:

(A)666° A/div.
(B) $6 \times 10^{-3}$ A/div.
(C)333° A/div.
(D) $3 \times 10^{-3}$ A/div.

Q62·PhysicsSingle correctJEE Main 2020

Using screw gauge of pitch 0.1 cm and 50 divisions on its circular scale, the thickness of an object is measured. It should correctly be recorded as

(A)2.121 cm
(B)2.123 cm
(C)2.124 cm
(D)2.125 cm

Q63·PhysicsSingle correctJEE Main 2020

If the screw on a screw-gauge is given six rotations, it moves by 3 mm on the main scale. If there are 50 divisions on the circular scale the least count of the screw gauge is

(A)0.001 cm
(B)0.001 mm
(C)0.01 cm
(D)0.02 mm

Q64·PhysicsNumericalJEE Main 2020

In a meter bridge experiment S is a standard resistance. R is a resistance wire. It is found that balancing length is

\ell

= 25 cm. If R is replaced by a wire of half length and half diameter that of R of same material, then the balancing distance

\ell'

(in cm) will now be __________.

Q65·PhysicsMultiple correctJEE Advanced 2019

Two identical moving coil galvanometers have 10 Ω resistance and full scale deflection at 2 μA current. One of them is converted into a voltmeter of 100 mV full scale reading and the other into an Ammeter of 1mA full scale current using appropriate resistors. These are then used to measure the voltage and current in the Ohm's law experiment with R = 1000 Ω resistor by using an ideal cell. Which of the following statement(s) is/are correct?

(A)The measured value of R will be 978 Ω < R < 982 Ω
(B)The resistance of the Voltmeter will be 100 kΩ
(C)If the ideal cell is replaced by a cell having internal resistance of 5Ω then the measured value of R will be more than 1000 Ω
(D)The resistance of the Ammeter will be 0.02Ω (round off to $2^{nd}$ decimal place)

Q66·PhysicsNumericalJEE Advanced 2019

An optical bench has 1.5 m long scale having four equal divisions in each cm. While measuring the focal length of a convex lens, the lens is kept at 75 cm mark of the scale and the object pin is kept at 45 cm mark. The image of the object pin on the other side of the lens overlaps with image pin that is kept at 135 cm mark. In this experiment, the percentage error in the measurement of the focal length of the lens is________.

Q67·PhysicsSingle correctJEE Main 2019

To verify Ohm's law, a student connects the voltmeter across the battery as, shown in the figure. The measured voltage is plotted as a function of the current, and the following graph is obtained: If V

_0

is almost zero, identify the correct statement:

(A)The potential difference across the battery is 1.5 V when it sends a current of 1000 mA.
(B)The emf of the battery is 1.5 V and the value of R is 1.5 $\Omega$
(C)The emf of the battery is 1.5 V and its internal resistance is 1.5 $\Omega$
(D)The value of the resistance R is 1.5 $\Omega$

Q68·PhysicsSingle correctJEE Main 2019

In a meter bridge experiment, the circuit diagram and the corresponding observation table are shown in figure. Which of the readings is inconsistent?

Sl. No.	R ( $\Omega$ )	l (cm)
1.	1000	60
2.	100	13
3.	10	1.5
4.	1	1.0

(A)4
(B)3
(C)2
(D)1

Q69·PhysicsSingle correctJEE Main 2019

In a simple pendulum experiment for determination of acceleration due to gravity (g), time taken for 20 oscillations is measured by using a watch of 1 second least count. The mean value of time taken comes out to be 30s.. The length of pendulum is measured by using a meter scale of least count 1 mm and the value obtained is 55.0 cm. The percentage error in the determination of g is close to:

(A)0.7 %
(B)3.5%
(C)6.8%
(D)0.2%

Q70·PhysicsSingle correctJEE Main 2019

In a Wheatstone bridge (see figure) Resistance P and Q are approximately equal. When R = 400

\Omega

, the bridge is balanced. On interchanging P and Q, the value of R, for balance is 405

\Omega

. The value of X is close to:

(A)401.5 ohm
(B)404.5 ohm
(C)403.5 ohm
(D)402.5 ohm

Q71·PhysicsSingle correctJEE Main 2019

In the experimental setup of metre bridge shown in the figure, the null point is obtained at a distance of 40cm from A. If a 10Ω resistor is connected in series with R

_1

, the null point shifts by 10cm. The resistance that should be connected in parallel with (R

_1

+ 10)Ω such that the null point shifts back to its initial position is:

(A)20Ω
(B)40Ω
(C)60Ω
(D)30Ω

Q72·PhysicsSingle correctJEE Main 2019

A 2 W carbon resistor is color coded with green, black, red and brown respectively. The maximum current which can be passed through this resistor is:

(A)20 mA
(B)100 mA
(C)0.4 mA
(D)63 mA

Q73·PhysicsSingle correctJEE Main 2019

A carbon resistance has a following colour code. What is the value of the resistance?

(A)530 kΩ ± 5%
(B)5.3 MΩ ± 5%
(C)6.4 MΩ ± 5%
(D)64 kΩ ± 10%

Q74·PhysicsSingle correctJEE Main 2019

A resistance is shown in the figure. Its value and tolerance are given respectively by:

(A)270 $\Omega$ , 10%
(B)27 k $\Omega$ , 10%
(C)27 k $\Omega$ , 20%
(D)270 $\Omega$ , 5%

Q75·PhysicsSingle correctJEE Main 2019

The pitch and the number of divisions, on the circular scale, for a given screw gauge are 0.5 mm and 100 respectively. When the screw gauge is fully tightened without any object, the zero of its circular scale lies 3 divisions below the mean line. The readings of the main scale and the circular scale for a thin sheet, are 5.5 mm and 48 respectively, the thickness of this sheet is

(A)5.755 mm
(B)5.950 mm
(C)5.725 mm
(D)5.740 mm

Q76·PhysicsSingle correctJEE Advanced 2016

There are two Vernier calipers both of which have 1 cm divided into 10 equal divisions on the main scale. The Vernier scale of one of the calipers (

C_{1}

) has 10 equal divisions that correspond to 9 main scale divisions. The Vernier scale of the other caliper (

C_{2}

) has 10 equal divisions that correspond to 11 main scale divisions. The readings of the two calipers are shown in the figure. The measured values (in cm) by calipers

C_{1}

and

C_{2}

respectively, are

(A)2.87 and 2.86
(B)2.87 and 2.87
(C)2.87 and 2.83
(D)2.85 and 2.82

Q77·PhysicsMultiple correctJEE Advanced 2015

Consider a Vernier callipers in which each 1 cm on the main scale is divided into 8 equal divisions and a screw gauge with 100 divisions on its circular scale. In the Vernier callipers, 5 divisions of the Vernier scale coincide with 4 divisions on the main scale and in the screw gauge, one complete rotation of the circular scale moves it by two divisions on the linear scale. Then:

(A)If the pitch of the screw gauge is twice the least count of the Vernier callipers, the least count of the screw gauge is 0.01 mm.
(B)If the pitch of the screw gauge is twice the least count of the Vernier callipers, the least count of the screw gauge is 0.005 mm.
(C)If the least count of the linear scale of the screw gauge is twice the least count of the Vernier callipers, the least count of the screw gauge is 0.01 mm.
(D)If the least count of the linear scale of the screw gauge is twice the least count of the Vernier callipers, the least count of the screw gauge is 0.005 mm.

Q78·PhysicsSingle correctJEE Advanced 2014

During an experiment with a metre bridge, the galvanometer shows a null point when the jockey is pressed at 40.0 cm using a standard resistance of 90

\Omega

, as shown in the figure. The least count of the scale used in the metre bridge is 1 mm. The unknown resistance is

(A) $60 \pm 0.15\,\Omega$
(B) $135 \pm 0.56\,\Omega$
(C) $60 \pm 0.25\,\Omega$
(D) $135 \pm 0.23\,\Omega$

Experimental Skills — frequently asked

How many questions from Experimental Skills appear in JEE?

Experimental Skills has appeared in 68 of the last 186 JEE Main and JEE Advanced papers — about 37% of them — contributing 78 questions in total across those papers.

Is Experimental Skills an important chapter for JEE?

Judged by how often it is actually tested, it appears in roughly 37% of papers. Chapters above about 50% are effectively guaranteed to show up every session, so they repay thorough preparation; lower-frequency chapters are better treated as targeted revision.

Where do these Experimental Skills questions come from?

Every question is from an official JEE Main or JEE Advanced paper, transcribed from the original paper and tagged to this chapter. Answers follow the official answer key.

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