JEE Main Physics Mock Test- 4

Question 1

Suppose an electron is attracted towards the origin by a force k/r where 'k' is a constant and 'r' is the distance of the electron from the origin . By applying Bohr model to this system , the radius of the n^th orbital of the electron is found to be 'r'_n and the kinetic energy of the electron to be T_n . Then which of the following is true ?

Accepted Answer

T_n independent of n , r_n ∝ n

Answer

T_n ∝ 1 ∕ n² , r_n ∝ n²

Answer

T_n ∝ 1 ∕ n , r_n ∝ n

Answer

T_n ∝ 1 ∕ n , r_n ∝ n²

Question 2

The energy of a photon of wavelength (λ) is

Accepted Answer

Answer

Answer

Answer

Question 3

For a given material, the Young's modulus is 2.4 times that of rigidity modulus. Its Poisson's ratio is

Accepted Answer

Answer

Answer

Answer

Question 4

Two spherical conductors of radii 4 cm and 5 cm are charged to the same potential. If σ₁ and σ₂ be the respective values of the surface density of charge on both the conductors, then the ratio σ₁/σ₂ is

Accepted Answer

Answer

Answer

Answer

Question 5

A transformer is used to reduce the mains supply of 220 V to 11 V. If the currents in primary and secondary coils are 5 A and 90 A respectively, efficiency of transformer is

Accepted Answer

Answer

Answer

Answer

Question 6

If 3.8 x 10^-6 is added to 4.2 x 10^-5 giving due regard to significant figures, then the result will be

Accepted Answer

4.6 x 10^-5

Answer

4.58 x 10^-5

Answer

4.5 x 10^-5

Answer

None of these

Question 7

A parallel plate capacitor is first charged and then a dielectric slab is introduced between the plates after disconnecting it from the battery. The quantity that remains unchanged is

Accepted Answer

<p>charge</p>

Answer

<p>energy</p>

Answer

<p>potential</p>

Answer

capacitance

Question 8

Spot the wrong statement : The acceleration due to gravity decreases if

Accepted Answer

We go from the equator towards the poles on the surface of earth

Answer

We go down from the surface of earth towards its centre

Answer

We go up from the surface of earth

Answer

The rotational velocity of earth is increased

Question 9

For Boyle's law to hold the gas should be

Accepted Answer

Perfect and of constant mass and temperature

Answer

Real and of constant mass and temperature

Answer

Perfect and at constant temperature but variable mass

Answer

Real and at constant temperature but variable mass

Question 10

If two bodies are projected at 30^o and 60^o respectively, with the same velocity, then

Accepted Answer

Their ranges are same

Answer

Their heights are same

Answer

Their times of flight are same

Answer

All of these

Question 11

When two deuterium nuclei fuse together, in addition to tritium, we get a

Accepted Answer

<p>Proton</p>

Answer

<p>Neutron</p>

Answer

<p>Deutron</p>

Answer

α - particle

Question 12

In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): A uniform solid cylinder rolling with angular velocity ω along a plane surface strikes a vertical rigid wall. Angular velocity of cylinder when it begins to roll up a wall is less than the initial Angular velocity (ω).
Reason(R): After striking the vertical wall angular velocity increases.

Accepted Answer

Assertion is true but Reason is false.

Answer

Both Assertion and Reason are true and Reason is the correct explanation of assertion.

Answer

Both Assertion and Reason are true and Reason is not the correct explanation of assertion

Answer

Assertion is false but Reason is true.

Question 13

In the following question, a Statement of Assertion (A) is given followed by a corresponding Reason (R) just below it. Read the Statements carefully and mark the correct answer-
Assertion(A): Current is passed through a metallic wire heating it red. When cold water is poured on half of its portion, the rest of half portion becomes more hot.
Reason(R): Resistance decreases due to decrease in temperature and then current through wire increases.

Accepted Answer

Both Assertion and Reason are true and Reason is the correct explanation of assertion.

Answer

Both Assertion and Reason are true and Reason is not the correct explanation of assertion

Answer

Assertion is true but Reason is false.

Answer

Assertion is false but Reason is true.

Question 14

A disc is placed on a surface of pond which has refractive index 5/3. A source of light is placed 4 m below the surface of liquid. The minimum radius of disc needed so that light is not coming out is

Accepted Answer

Answer

Answer

Answer

Question 15

Sound waves transfer

Accepted Answer

both energy and momentum

Answer

only energy not momentum

Answer

<h5>                                  energy                               </h5>

Answer

<h5>                                  momentum                               </h5>

Question 16

The wavelength of ultrasonic waves in air is of the order of

Accepted Answer

5 x 10^-5 cm

Answer

5 x 10^-8 cm

Answer

5 x 10⁵ cm

Answer

5 x 10⁸ cm

Question 17

70 calories of heat are required to raise the temperature of 2 moles of an ideal gas at constant pressure from 30^oC to 35^oC. The amount of heat required to raise the temperature of the same sample of the gas through the same range at constant volume is nearly (Gas constant = 1.99 cal/K-mole)

Accepted Answer

Answer

Answer

Answer

Question 18

Both light and sound waves produce diffraction. It is more difficult to observe the diffraction with light waves because

Accepted Answer

Wavelength of light waves is far smaller

Answer

Light wave do not require medium

Answer

Light waves are transverse

Answer

Speed of light is far greater

Question 19

A boy of mass 42 Kg eats bananas of 980 calories. If this energy is used up to lift him from the ground, the height to which he can move up is

Accepted Answer

Answer

Answer

Answer

Question 20

In the given circuit the capacitor (C) may be charged through resistance R by battery V by closing switch S₁. Also when S₁ is opened and S₂ is closed the capacitor is connected in series with inductor (L).

Q. At the start, the capacitor was uncharged. When switch S₁ is closed and S₂ is kept open, the time constant of this circuit is τ. Which of the following is correct?

Accepted Answer

After time interval 2τ, charge on the capacitor is cv(1-e^-2)

Answer

After time interval τ, charge on the capacitor is cv/2

Answer

The work done by the voltage source will be half of the heat dissipated when the capacitor is fully charge

Answer

After time interval 2t, charge on the capacitor is cv(1-e^-1)

Question 21

A plastic circular disc of radius 10 cm is placed on a thin oil film of thickness 2 mm, spread over a flat horizontal surface. The torque (N-m) required to spin the disc about its central vertical axis with a constant angular velocity 8 rad/sec is (coefficient of viscosity of oil is 1.0 kg/m-s) (take π = 3.14)

Accepted Answer

Question 22

Calculate the value of output voltage V₀ (in V) if the Si diode and Ge diode conduct at 0.7 V and 0.3V respectively as shown in figure.

Accepted Answer

Question 23

In Young's double slit experiment, the wavelength of red light is 7800 Å and that of blue light is 5200 Å. The minimum value of n for which n^th bright band due to red light coincides with (n + 1)^th bright band due to blue light, is :

Accepted Answer

Question 24

A railway track (made of iron) is laid in winter when the average temperature is 18°C. The track consists of sections of 12.0 m placed on after the other. How much gap (in cm) should be left between two such sections so that there is no compression during summer when the maximum temperature goes to 48°C ? Coefficient of linear expansion of iron = 11 × 10^–6/°C.

Accepted Answer

Question 25

A string of mass per unit length μ is clamped at both ends such that one end of the string is at x = 0 and the other end at x = L. When string vibrates in fundamental mode, amplitude of the midpoint of string is a and tension in string is F. Find the total oscillation energy (in J) stored in the string. (Use L = 1m, F = 10 N, a = 1/πm)

Accepted Answer

JEE Main Physics Mock Test- 4 Free Online Test 2026

Full Mock Test & Solutions: JEE Main Physics Mock Test- 4 (25 Questions)

The energy of a photon of wavelength (λ) is

For a given material, the Young's modulus is 2.4 times that of rigidity modulus. Its Poisson's ratio is

Two spherical conductors of radii 4 cm and 5 cm are charged to the same potential. If σ₁ and σ₂ be the respective values of the surface density of charge on both the conductors, then the ratio σ₁/σ₂ is

A transformer is used to reduce the mains supply of 220 V to 11 V. If the currents in primary and secondary coils are 5 A and 90 A respectively, efficiency of transformer is

If 3.8 x 10^-6 is added to 4.2 x 10^-5 giving due regard to significant figures, then the result will be

A parallel plate capacitor is first charged and then a dielectric slab is introduced between the plates after disconnecting it from the battery. The quantity that remains unchanged is

Spot the wrong statement : The acceleration due to gravity decreases if

For Boyle's law to hold the gas should be

If two bodies are projected at 30^o and 60^o respectively, with the same velocity, then

When two deuterium nuclei fuse together, in addition to tritium, we get a

A disc is placed on a surface of pond which has refractive index 5/3. A source of light is placed 4 m below the surface of liquid. The minimum radius of disc needed so that light is not coming out is

Sound waves transfer

The wavelength of ultrasonic waves in air is of the order of

70 calories of heat are required to raise the temperature of 2 moles of an ideal gas at constant pressure from 30^oC to 35^oC. The amount of heat required to raise the temperature of the same sample of the gas through the same range at constant volume is nearly (Gas constant = 1.99 cal/K-mole)

Both light and sound waves produce diffraction. It is more difficult to observe the diffraction with light waves because

A boy of mass 42 Kg eats bananas of 980 calories. If this energy is used up to lift him from the ground, the height to which he can move up is

Calculate the value of output voltage V₀ (in V) if the Si diode and Ge diode conduct at 0.7 V and 0.3V respectively as shown in figure.

In Young's double slit experiment, the wavelength of red light is 7800 Å and that of blue light is 5200 Å. The minimum value of n for which n^th bright band due to red light coincides with (n + 1)^th bright band due to blue light, is :

Mock Tests for JEE Main and Advanced 2026

Mock Tests for JEE Main and Advanced 2026

Top Courses for JEE

About this JEE Mock Test

Explore more JEE Resources

JEE Main Physics Mock Test- 4 Free Online Test 2026

Full Mock Test & Solutions: JEE Main Physics Mock Test- 4 (25 Questions)

The energy of a photon of wavelength (λ) is

For a given material, the Young's modulus is 2.4 times that of rigidity modulus. Its Poisson's ratio is

Two spherical conductors of radii 4 cm and 5 cm are charged to the same potential. If σ₁ and σ₂ be the respective values of the surface density of charge on both the conductors, then the ratio σ₁/σ₂ is

A transformer is used to reduce the mains supply of 220 V to 11 V. If the currents in primary and secondary coils are 5 A and 90 A respectively, efficiency of transformer is

If 3.8 x 10-6 is added to 4.2 x 10-5 giving due regard to significant figures, then the result will be

A parallel plate capacitor is first charged and then a dielectric slab is introduced between the plates after disconnecting it from the battery. The quantity that remains unchanged is

Spot the wrong statement : The acceleration due to gravity decreases if

For Boyle's law to hold the gas should be

If two bodies are projected at 30o and 60o respectively, with the same velocity, then

When two deuterium nuclei fuse together, in addition to tritium, we get a

A disc is placed on a surface of pond which has refractive index 5/3. A source of light is placed 4 m below the surface of liquid. The minimum radius of disc needed so that light is not coming out is

Sound waves transfer

The wavelength of ultrasonic waves in air is of the order of

70 calories of heat are required to raise the temperature of 2 moles of an ideal gas at constant pressure from 30oC to 35oC. The amount of heat required to raise the temperature of the same sample of the gas through the same range at constant volume is nearly (Gas constant = 1.99 cal/K-mole)

Both light and sound waves produce diffraction. It is more difficult to observe the diffraction with light waves because

A boy of mass 42 Kg eats bananas of 980 calories. If this energy is used up to lift him from the ground, the height to which he can move up is

Calculate the value of output voltage V0 (in V) if the Si diode and Ge diode conduct at 0.7 V and 0.3V respectively as shown in figure.

In Young's double slit experiment, the wavelength of red light is 7800 Å and that of blue light is 5200 Å. The minimum value of n for which nth bright band due to red light coincides with (n + 1)th bright band due to blue light, is :

Mock Tests for JEE Main and Advanced 2026

Mock Tests for JEE Main and Advanced 2026

Top Courses for JEE

About this JEE Mock Test

Explore more JEE Resources

If 3.8 x 10^-6 is added to 4.2 x 10^-5 giving due regard to significant figures, then the result will be

If two bodies are projected at 30^o and 60^o respectively, with the same velocity, then

70 calories of heat are required to raise the temperature of 2 moles of an ideal gas at constant pressure from 30^oC to 35^oC. The amount of heat required to raise the temperature of the same sample of the gas through the same range at constant volume is nearly (Gas constant = 1.99 cal/K-mole)

Calculate the value of output voltage V₀ (in V) if the Si diode and Ge diode conduct at 0.7 V and 0.3V respectively as shown in figure.

In Young's double slit experiment, the wavelength of red light is 7800 Å and that of blue light is 5200 Å. The minimum value of n for which n^th bright band due to red light coincides with (n + 1)^th bright band due to blue light, is :