Physics class tests for XII/ICSE/CBSE

SUB: PHYSICS                                  Test: Class test (Not taken)

Question 1

Derive potential due to an electric dipole in a general direction making an angle J with dipole axis. Use E = -dV/dr to obtain E in general direction.

Question 2

Derive electric field in the end-on and broad-on position for a dipole vector P = p 2Q.a, where P is the vector and p the unit vector along the same.

Question 3

Describe the Rutherford’s model of the atom. Explain the results of the Geiger-Marsden experiment with a diagram. Mention the Rutherford’s model’s drawback.

Question 4

(Briefly) state a few postulates of the Bohr’s atomic model. Obtain an expression for quantized energy orbits.

E_n = – (me⁴/8Є₀²h²) 1/n²

by using r_n = n² (Є₀h²)/(pme²) and v_n = 1/n (e²)/(2Є₀h).

Note: write in a few steps, all details are not required.

Question 5

Derive the expression for radioactive decay N = N₀ e^-λt. From there define and obtain T_1/2 (Half-life), in terms of λ.