Alternating Current — Physics STD 12 Science — Question

If six identical cells each having an e.m.f. of 6V are connected in parallel, the e.m.f. of the combination is

(a) 1 V

(b) 36 V

(c)

(d) 6 V

In the equation AB = C, A is the current density, C is the electric field, Then B is:

If energy of K-shell electron is – 40000 eV  and If 60000 V  potential is applied at coolidge tube then which of the following X-ray will get form

(a) Continuous

(b) White X-rays

(c) Continuous and all series of characteristic

(d) None of these

Assertion :   X-rays cannot be diffracted by means of grating.

Reason     : X-rays does not obey Bragg's law.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If the assertion and reason both are false.

A light has amplitude A and angle between analyser and polariser is 60°. Light is reflected by analyser has amplitude

(a) A

(b) A/

(c) A/2

(d) A/2

In a certain arrangement, a proton does not get deflected while moving through a magnetic field region. Under what condition is it possible?

Dimensions of permeability is :

 Find equivalent capacitance between A and B

Excitation energy of a hydrogen like ion in its first excitation state is 40.8 eV. Energy needed to remove the electron from the ion in ground state is

(a) 54.4 eV

(b) 13.6 eV

(c) 40.8 eV

(d) 27.2 eV

What is the study of electric charges in motion called?