## Physics Preparatory Test for Quarterly, Class XII, –I

Question 1
What’s the work done to take a charge Q on a circular voyage, on an equipotential surface?

A. Zero
B. Depends on radius of circle
C. Depends on distance from center of equipotential surface
D. Q/epsilon_0

Rutherford’s atomic model is based on which fact

A. Geiger Marsden scattering of alpha-{particles} suggests presence of nucleus.

B. Smith’s electrodes dipped in electrochemical material

C. Quantization of charge     D. Quantization of angular momentum

Question 6
What’s the typical energy output range of Indian nuclear reactors?

Question 7
Which of the following physical quantity is scalar: electric field intensity, electric potential, dipole moment?

Question 9
Use superposition principle of electric field intensity of two charges, to obtain the electric field intensity E of a dipole along the dipole axis. This is known as electric field for the End-on configuration.

Also use the same idea to obtain the potential at a point vertical to the dipole axis. This is known as potential for the Broad-on configuration.

Question 10
Obtain the electric field intensity E of a dipole vertical to the dipole axis, i.e. — Broad-on electric field. Also obtain the potential at a point on the dipole axis, i.e. — End-on potential.

Question 17
Describe the Van-de-Graaff generator, its principle, working and use.

## Physics Preparatory Test for Quarterly, Class XII, –II

Physics preparatory tests for PUC, ISc, class XII in the CBSE, ICSE (CISCE), State boards.
Subject: Physics

Test: Preparatory test — II. Pre-Quarterly.
Class: PUC — II (also good for ISC — II)
date: 25 the June 2013.
Time: 1.5 hours.
Total marks: 50

Instructions.

— Numerical problems solved without writing the relevant formulas carry no marks.

— Answers without relevant diagrams, circuits wherever necessary will not carry any marks.

PART-A
I. Answer all the following questions (1 X 5)
Question 1
Where would Coulomb’s interaction be weaker, in dielectric medium or vacuum?

Question 2
Between a dipole and a point charge whose electric potential reduces faster?

Question 3
What is the work done when a charge makes a rectangular path on an equipotential surface?

Question 4
Write the de-Broglie formula for wavelength of a wave-particle if its momentum is p?

Question 5
Define refractive index from angle of incidence and angle of reflection.

PART-B
II. Answer any Five of the following questions, 2 marks each.   (2 X 5=10)
Question 6
State how density of electric lines of force is related to the electric field vector intensity E. Also mention another property of the lines of force and one property of the equipotential surface.

Question 7
Write the Gauss law of electrostatics and define electric flux for a uniform field E.

Question 8
How one defines the direction of a dipole vector? What’s the potential vertical to the dipole axis?

V. Answer any three of the following questions (5 X 3)
Question 19
A proton has a radius R and the charge Q is uniformly distributed. Use Bohr’s atomic energy level formula for the 1st excited state (n = 2) and ground state (n = 1) to obtain energy of the Hydrogen-atom.

Question 21
Draw a simple and neat diagram showing a convex lens, optical center and focal point (focus). Now define power of a lens and obtain an expression for it.

## Class XII, ICSE exam questions, Physics, Updated Version 2

Question 6 [2+3+2]

Obtain an expression for the Nuclear Size of an atom by solving for distance of closest approach (r) which is also known as Impact Parameter (say l). Use an incoming alpha-particle of mass mα and charge q that’s deflected by the presence of a nucleus of atomic number Z to obtain l. Now replace the variables by some numerical: mα = 6.8×10-27kg, e = 1.6 x 10-19 coul, Z=14, and vα= 2.0×107 m/s. Express the answer in Femto-meters.

Question 7 [3+4]

A proton has a radius R and the charge Q is uniformly distributed. Use Bohr’s atomic energy level formula for the 1st excited state {n=2} energy of the Hydrogen-atom.

## Class XII, CBSE exam questions, Physics

Electrostatics

6. State how density of electric lines of force is related to the Electric Field Vector intensity E. Also mention another three properties of the lines of forces.

7. Write the vector expression for Coulomb’s law and state 3 forces that are conservative forces by nature.

8. What happens to the charge on a conducting shell? What happens to lines of forces when a conducting shell is present in the path of the lines of forces?

## Class XII, ICSE exam questions, Physics.

Question 1

(a) In an electric dipole, how is the direction of the dipole vector defined?

(b) What’s the Electric Potential of a Dipole Vector in the vertical direction to it?

(c) Say if this is correct or incorrect: “Between an alpha-particle and a proton the alpha particle has more electrostatics potential energy in an electrostatics potential of 100 volt.”?

(d) Give example of 3 conservative forces and state if this is true or not-true: “The work done in a conservative force field during a circular voyage is proportional to the amount of charge on the voyage”?