CBSE Class 12 Physics Sample Paper 2023

1 According to Coulomb's law, which is the correct relation for the following figure? (Image) 
(i) q1 q2> 0
(ii) q1 q2<0
(iii) q1 q2 =0
(iv) 1> q1/ q2 > 0

Answer : (ii) 

2 The electric potential on the axis of an electric dipole at a distance 'r from it’s centre is V. Then the potential at a point at the same distance on its equatorial line will be
(i) 2V
(ii) -V
(iii) V/2
(iv) Zero

Answer : (iv) 

3 The temperature (T) dependence of resistivity of materials A and material B is represented by fig (i) and fig (ii) respectively.
Identify material A and material B. (Image)
i) material A is copper and material B is germanium
(ii) material A is germanium and material B is copper
(iii) material A is nichrome and material B is germanium
(iv) material A is copper and material B is nichrome

Answer : (ii) 

4 Two concentric and coplanar circular loops P and Q have their radii in the ratio 2:3. Loop Q carries a current 9 A in the anticlockwise direction. For the magnetic field to be zero at the
common centre, loop P must carry
(i) 3A in clockwise direction
(ii) 9A in clockwise direction
(iii) 6 A in anti-clockwise direction
(iv) 6 A in the clockwise direction.

Answer : (iv) 

5 A long straight wire of circular cross section of radius a carries a steady current I. The current is uniformly distributed across its cross section. The ratio of the magnitudes of magnetic field at a point distant a/2 above the surface of wire to that at a point distant a/2 below its surface is
(i) 4 :1
(ii) 1:1
(iii) 4: 3
(iv) 3 :4

Answer : (iii) 

6 If the magnetizing field on a ferromagnetic material is increased,its permeability
(i) decreases
(ii) increases
(iii) remains unchanged
(iv) first decreases and then increases

Answer : (i) 

7 An iron cored coil is connected in series with an electric bulb with an AC source as shown in figure. When iron piece is taken out of the coil, the brightness of the bulb will (Image)
(i) decrease
(ii) increase
(iii) remain unaffected
(iv) fluctuate

Answer : (ii) 

8 Which of the following statement is NOT true about the properties of electromagnetic waves?
(I) These waves do not require any material medium for their propagation
(ii) Both electric and magnetic field vectors attain the maxima and minima at the same time
(iii) The energy in electromagnetic wave is divided equally between electric and magnetic fields
(iv) Both electric and magnetic field vectors are parallel to each other

Answer : (iv) 

9 A rectangular, a square, a circular and an elliptical loop, all in the (x-y) plane, are moving out of a uniform magnetic field with a constant velocity v = vi.The magnetic field is directed along the negative z-axis direction. The induced emf, during the passage of these loops, out of the field region, will not remain constant for
(i) any of the four loops
(ii) the circular and elliptical loops
(iii) the rectangular, circular and elliptical loops
(iv) only the elliptical loops

Answer : (ii) 

10 In a Young’s double slit experiment, the path difference at a certain point on the screen between two interfering waves is th of the wavelength. The ratio of intensity at this point to that at the centre of a bright fringe is close to
(i) 0.80
(ii) 0.74
(iii) 0.94
(iv) 0.85

Answer : (iv) 

11 The work function for a metal surface is 4.14 eV. The threshold wavelength for this metal surface is:
(i) 4125 Å
(ii) 2062.5 Å
(iii) 3000 Å
(iv) 6000 Å

Answer : (iii) 

12 The radius of the innermost electron orbit of a hydrogen atom is 5.3×10^–11 m. The radius of the n =3 orbit is
(i) 1.01 x 10-10m
(ii) 1.59 X 10-10m
(iii) 2.12 x 10-10m
(iv) 4.77 X 10-10m

Answer : (iv) 

13 Which of the following statements about nuclear forces is not true?
(i) The nuclear force between two nucleons falls rapidly to zero as their distance is more than a few femtometres.
(ii) The nuclear force is much weaker than the Coulomb force.
(iii) The force is attractive for distances larger than 0.8 fm and repulsive if they are separated by distances less than 0.8 fm.
(iv) The nuclear force between neutron-neutron, proton-neutron and proton-proton is approximately the same.

Answer : (ii)