Subject

Physics

Class

CBSE Class 12

Pre Boards

Practice to excel and get familiar with the paper pattern and the type of questions. Check you answers with answer keys provided.

Sample Papers

Download the PDF Sample Papers Free for off line practice and view the Solutions online.

 Multiple Choice QuestionsShort Answer Type

1.

A point charge +Q is placed at point O as shown in the figure. Is the potential
difference VA – VB is positive, negative or zero?


A point charge +Q is placed at point O as shown in the figure. Is the potential
difference VA – VB is positive, negative or zero?

8261 Views

2. How does the electric flux due to a point charge enclosed by a spherical Gaussian surface get affected when its radius is increased?

How does the electric flux due to a point charge enclosed by a spherical Gaussian surface get affected when its radius is increased?
3127 Views

3. A charge is distributed uniformly over a ring of radius 'a'. Obtain an expression for the electric intensity E at a point on the axis of the ring. Hence, show that for points at large distance from the ring, it behaves like a point charge.

A charge is distributed uniformly over a ring of radius 'a'. Obtain an expression for the electric intensity E at a point on the axis of the ring. Hence, show that for points at large distance from the ring, it behaves like a point charge.
4335 Views

4. Define 'quality factor' of resonance in a series LCR circuit. What is its SI unit?

Define 'quality factor' of resonance in a series LCR circuit. What is its SI unit?
5365 Views

5.

i) Define mutual Inductance. 

ii) A pair of adjacent coils has a mutual inductance of 1.5 H. If the current in one coil changes 20 A in 0.5 s, what is the change of flux linkage with the other coil?


i) Define mutual Inductance. 

ii) A pair of adjacent coils has a mutual inductance of 1.5 H. If the current in one coil changes 20 A in 0.5 s, what is the change of flux linkage with the other coil?

3164 Views

6. Two cells of emfs 1.5 V and 2.0 V,  having internal resistances 0.2 Ω and 0.3 Ω, respectively, are connected in parallel. Calculate the emf and internal resistance of the equivalent cell.

Two cells of emfs 1.5 V and 2.0 V,  having internal resistances 0.2 Ω and 0.3 Ω, respectively, are connected in parallel. Calculate the emf and internal resistance of the equivalent cell.
3788 Views

7. Write the underlying principle of a moving coil galvanometer.

Write the underlying principle of a moving coil galvanometer.
2229 Views

8.

a) Write the expression for the magnetic force acting on a charged particle moving with velocity v in the presence of magnetic field B. 

b) A neutron, an electron and an alpha particle, moving with equal velocities, enter a uniform magnetic field going into the plane of paper, as shown. Trace their paths in the field and justify your answer. 


a) Write the expression for the magnetic force acting on a charged particle moving with velocity v in the presence of magnetic field B. 

b) A neutron, an electron and an alpha particle, moving with equal velocities, enter a uniform magnetic field going into the plane of paper, as shown. Trace their paths in the field and justify your answer. 

3384 Views

9. Why are microwaves considered suitable for radar systems used in aircraft navigation?

Why are microwaves considered suitable for radar systems used in aircraft navigation?
4779 Views

10. Two parallel-plate capacitors X and Y have the same area of plates and same separation between them. X has air between the plates, while Y contains a dielectric medium of straight epsilon subscript straight r space end subscript equals space 4



i) Calculate capacitance of each capacitor if the equivalent capacitance of the combination is 4 μF
ii) Calculate the potential difference between the plates x and Y

iii) Estimate the ratio of electrostatic energies stored in x and Y

Two parallel-plate capacitors X and Y have the same area of plates and same separation between them. X has air between the plates, while Y contains a dielectric medium of straight epsilon subscript straight r space end subscript equals space 4



i) Calculate capacitance of each capacitor if the equivalent capacitance of the combination is 4 μF
ii) Calculate the potential difference between the plates x and Y

iii) Estimate the ratio of electrostatic energies stored in x and Y
3651 Views