HIGHER ORDER THINKING SKILLS EXAMPLARY QUESTIONS XII PHYSICS

A Physics – Class XII

Q.1 Four point charges are placed at the four corners of a square in the two ways (i) and (ii) as shown below. Will the (i) electric field (ii) Electric potential, at the centre of the square, be the same or different in the two configrations and why?

(2 marks)

Q.2 The two graphs drawn below, show the variation of electrostatic potential V with 1/r, r being the distance of the field point from the point charge, for two point charges q3 and q4.

(i) What are the signs of the two charges?
(ii) Which of the two charges has a larger magnitude and why?
(2 Marks)

Q.3 An electrical element X, when connected to an alternating voltage source, has the current through it leading the voltage by Π/2 (pie/2) radii. Sketch a graph showing the variation in opposition offered by it to the current with the frequency of the applied voltage.
(1 Mark)


Q.4 The spectrum of a star in the visible and the ultraviolet region was observed. The wavelength of some of the lines that could be identified were found to be :

824 A0, 970 A0, 1120 A0, 2504 A0, 5173 A0 and 6100 A0

Which of these spectral lines cannot belong to hydrogen atom spectrum ?
Given Rydberg Constant R = 1.03 x 10+7 m-1 and 1/R = 970 A0
Support your answer with suitable calculations.

(3 marks)