Electromagnetic Waves — Physics STD 12 Science — Question

When a thin transparent plate of thickness t and refractive index m is placed in the path of one of the two interfering waves of light, then the path difference changes by

(a) (m + 1)t

(b) (m – 1)t

(c)

(d)

The current flowing in a coil of self inductance 0.4 mH is increased by 250 mA in 0.1 sec. The e.m.f. induced will be

(a) + 1 V

(b) – 1 V

(c) + 1 mV

(d) – 1 mV

The transverse nature of light is shown by

(a) Interference of light

(b) Refraction of light

(c) Polarisation of light

(d) Dispersion of light

Assertion  :   The phenomenon of ­X-ray production is basically inverse of photoelectric effect.    

Reason      :  X-rays are electromagnetic waves.

(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.

The ability of an optical instruments to show the images of two adjacent point objects as separate is called:

An electron is moving along the positive X-axis. You want to apply a magnetic field for a short time so that the electron may reverse its direction and move parallel to the negative X-axis. This can be done by applying the magnetic field along

(a) Y-axis

(b) X-axis

(c) Y-axis only

(d) None of these

The ratio of momenta of an electron and an α- particle which are accelerated from rest by a potential difference of 100 V is

(a) 1

(b)

(c)

(d)

Polarization of light confirms :

A potentiometer is an accurate and versatile device to make electrical measurements of E.M.F. because the method involves:

The equivalent capacitance of the combination shown in figure is: