# Class 12 Physics Sample Paper With Solutions Set B

Please refer to Class 12 Physics Sample Paper With Solutions Set B below. These Class 12 Physics Sample Papers will help you to get more understanding of the type of questions expected in the upcoming exams. All sample guess papers for Physics Class 12 have been designed as per the latest examination pattern issued by CBSE. Please practice all CBSE Sample Papers for Physics in Standard 12.

## Sample Paper Class 12 Physics With Solutions Set B

1. A resistor has a colour code of green, blue, brown and silver. What is its resistance?
(a) 56 Ω ± 5%
(b) 560 Ω ± 10%
(c) 560 Ω ± 5%
(d) 5600 Ω ± 10%

B

2. Consider the following statements regarding the network shown in the figure

(1) The equivalent resistance of the network between points A and B is independent of value of G.
(2) The equivalent resistance of the network between points A and B is 4/3 R.
(3) The current through G is zero.
Which of the above statements is/are true?
(a) (1) only
(b) (2) only
(c) (2) and (3)
(d) (1), (2) and (3)

D

3. Particles that interact by the strong force are called
(a) leptons
(c) muons
(d) electrons

B

4. The plates of a parallel plate capacitor have an area of 90 cm2 each and are separated by 2.5 mm. The capacitor is charged by connecting it to a 400 V supply. How much electrical energy is stored by the capacitor?
(a) 2.55 × 10–6 J
(b) –2.55 × 10–6 J
(c) –2.05 × 10–6 J
(d) 2.05 × 10–6 J

A

5. The flux entering and leaving a closed surface are 5 × 105 and 4 × 105 MKS units respectively, then the charge inside the surface will be
(a) –8.85 × 10–7 C
(b) 8.85 × 10–7 C
(c) 8.85 × 107 C
(d) 6.85 × 10–7 C

A

6. Which of the following is not made by quarks?
(a) Neutron
(b) Positron
(c) Proton
(d) p-meson

B

7. Rising and setting sun appears to be reddish because of
(a) diffraction
(b) scattering due to dust particles and air molecules
(c) refraction
(d) polarization.

B

8. A conducting sphere of radius 10 cm is charged with 10 mC. Another uncharged sphere of radius 20 cm is allowed to touch it. After that if the spheres are separated, the surface density of charges on the spheres will be in the ratio of
(a) 1 : 4
(b) 1 : 2
(c) 1 : 3
(d) 2 : 1

D

9. A 4 m long wire of resistance 8 W is connected in series with a battery of emf 2 V and a resistor of 7 Ω. The internal resistance of the battery is 1 Ω. What is the potential gradient along the wire?
(a) 1.00 V m–1
(b) 0.75 V m–1
(c) 0.50 V m–1
(d) 0.25 V m–1

D

10. Excitation energy of a hydrogen like ion in its first excitation state is 40.8 eV. Energy needed to remove the electron from the ion in ground state is
(a) 54.4 eV
(b) 13.6 eV
(c) 40.8 eV
(d) 27.2 eV

A

11. Two coils have a mutual inductance 0.005 H. The current changes in the first coil according to equation I = I0sinωt, where I0 = 10 A and ω = 100π rad s–1. The maximum value of emf in the second coil is (in V)
(a) 2π
(b) 5π
(c) π
(d) 4π

B

12. Which of the energy band diagrams shown below corresponds to that of a semiconductor?

D

13. In the circuit shown in figure, the current gain, β = 100 for the transistor. What would be the base resistance RB so that VCE = 5V? (Neglect VBE).

(a) 2 × 103 Ω
(b) 2 × 105 Ω
(c) 1 × 106 Ω
(d) 500 Ω

B

14. In the propagation of electromagnetic waves, the angle between the direction of propagation  and plane of polarisation is
(a) 0°
(b) 45°
(c) 90°
(d) 180°

A

15. A long straight wire carrying a current of 30 A is placed in an external uniform  magnetic field of induction 4 × 10–4 T. The magnetic field is acting parallel to the  direction of current. The magnitude of the resultant magnetic induction in tesla at a point 2 cm away from the wire is
(μ0 = 4π × 10–7 H m–1)
(a) 10–4
(b) 3 × 10–4
(c) 5 × 10–4
(d) 6 × 10–4

C

16. The rate of change of current is 500 A s–1 at the instant the key is pressed in the circuit shown in figure. The current through the circuit is

(a) 2 A
(b) 1 A
(c) 0.5 A
(d) 1.5 A

B

17. One of the devices to produce plane polarised light is
(a) nicol prism
(b) mirror
(c) biprism
(d) half wave plate

A

18. In an electromagnetic wave, the electric and magnetic fields are 100 V m–1 and 0.265 A m–1. The maximum energy flow will be
(a) 79 W m–2
(b) 13.2 W m–2
(c) 53.0 W m–2
(d) 26.5 W m–2

D

19. There are three wavelengths : 10–8 m, 10–2 m, 108 m. Their respective names are
(a) visible rays, g-rays, ultraviolet rays

B

20. A Geiger counter is able to provide an indirect measure of radioactivity because radiation has a property of
(a) ionization
(b) making matter glow in the dark
(c) fogging photographic film
(d) altracting electrons

A

21. In the circuit shown in the figure, the switch S is closed at time t = 0.

(a) RC
(b) RC ln 2
(c) 1/RCln2
(d) LR

B

22. What is the net force on the rectangular coil shown in figure?

(a) 25 × 10–7 N towards wire
(b) 25 × 10–7 N away from wire
(c) 35 × 10–7 N towards wire
(d) 35 × 10–7 N away from wire

A

23. An electron having momentum 2.4 × 10–23 kg m s–1 enters a region of uniform magnetic field of 0.15 T. The field vector makes an angle of 30° with the initial velocity vector of the electron. The radius of the helical path of the electron in the field shall be.
(a) 2 mm
(b) 1 mm
(c) √3/2 mm
(d) 0.5 mm

D

24. An electron is moving in a cyclotron at a speed of 3.2 × 107 m s–1 in a magnetic field of 5 × 10–4 T perpendicular to it. What is the frequency of this electron?
(e = 1.6 × 10–19 C, me = 9.1 × 10–31 kg)
(a) 1.4 × 105 Hz
(b) 1.4 × 107 Hz
(c) 1.4 × 106 Hz
(d) 1.4 × 109 Hz

B

25. A ray of light moves from denser to rarer medium. Which of the following is correct?
(a) Energy increases
(b) Frequency increases
(c) Phase change by 90°
(d) Velocity increases

D

26. A 150 ohm resistor and an inductance L are connected in series to a 200 V, 50 Hz source of negligible impedance. The current comes to 1.0 A. When the source is changed to 400 V, 100 Hz, the current will be
(a) less than 1.0 A
(b) 1.0 A
(c) between 1 A and 2 A
(d) between 4 A and 2 A

C

27. The activity of a radioactive sample is measured as N0 counts per minute at t = 0 and N0/e counts per minute at t = 5 minutes. The time (in minutes) at which the activity  reduces to half its value is
(a) loge2/5
(b) 5/loge 2
(c) 5log10 2
(d) 5loge

D

28. The output Y of the logic circuit as shown in figure is

(a) (A + B) C
(b) (A + C) B
(c) (B + C) A
(d) A + B + C

A

29. The circuit shown in the figure contains two diodes each with a forward resistance of 30 Ω and with infinite backward resistance. If the battery is 3 V, the current through the 50 Ω resistance (in ampere) is

(a) zero
(b) 0.01
(c) 0.02
(d) 0.03

C

30. The distance between plates of a parallel plate capacitor is 5d. The positively charged plate is at x = 0 and negatively charged plate is at x = 5d. Two slabs one of conductor and the other of a dielectric of same thickness d are inserted between the plates as shown in figure. Potential (V) versus distance (x) graph will be

B

31. Let K1 be the maximum kinetic energy of photoelectrons emitted by light of wavelength λ1 and K2 corresponding to wavelength λ2. If λ1 = 2λ2 then
(a) 2K1 = K2
(b) K1 = 2K2
(c) K1 < K2/2
(d) K1 > 2K

C

32. A rigid circular loop of radius r and mass m lies in the x-y plane on a flat table and has a current I flowing in it. At this particular place, the earth’s magnetic field is B¯ = Bxî + B2k^ What is the value I so that one edge of the loop lifts from the table?

C

33. In the Young’s double slit experiment apparatus shown in figure, the ratio of maximum to  minimum intensity on the screen is 9. The wavelength of light used is l, then the value of y is

(a) λD/d
(b) λD/2d
(c) λD/3d
(d) λD/4d

C

34. Find the phase velocity of electromangetic wave having electron density and frequency for D layer, N = 400 electron per c.c., u = 200 kHz.
(a) 3 × 108 m s–1
(b) 3.4 × 108 m s–1
(c) 6.9 × 108 m s–1
(d) 1.1 × 109 m s–1

C

35. The magnifying power of a telescope is 9. When it is adjusted for parallel rays, the distance between the objective and theeye-piece is found to be 20 cm. The focal lengths of the lenses are
(a) 18 cm, 2 cm
(b) 11 cm, 9 cm
(c) 10 cm, 10 cm
(d) 15 cm, 5 cm

A

36. An object is placed 30 cm to the left of a diverging lens whose focal length is of magnitude 20 cm. Which one of the following correctly states the nature and position of the virtual image formed?
Nature of image        Distance from lens
(a) inverted, enlarged       60 cm to the right
(b) erect, diminished         12 cm to the left
(c) inverted, enlarged        60 cm to the left
(d) erect, diminished         12 cm to the right

B

37. The angular momentum of electron in 3d orbital of an atom is

C

38. The binding energy of an electron in the ground state of He is equal to 24.6 eV. The energy required to remove both the electrons is
(a) 49.2 eV
(b) 24.6 eV
(c) 38.2 eV
(d) 79.0 eV

D

39. A convex lens of focal length 0.15 m is made of a material of refractive index 3/2. When it is placed in a liquid, its focal length is increased by 0.225 m. The refractive index of the liquid is
(a) 7/4
(b) 5/4
(c) 9/4
(d) 3/2