Ray Optics and Optical Instruments — Physics STD 12 Science — Question

Smaller pieces of heavy stones and metals which on entering earth's atmosphere burns out are

(a) Comets

(b) Meteorites

(c) Asteroids

(d) All of these

Symbol of Inductance in electric circuit is-

Potential difference across the terminals of the battery shown in figure is (r = internal resistance of battery)

(a) 8 V

(b) 10 V

(c) 6 V

(d) Zero

Between the plates of a parallel plate condenser there is 1mm thick paper of dielectric constant 4. It is charged at 100 volt. The electric field in volt/metre between the plates of the capacitor is

(a) 100

(b) 100000

(c) 25000

(d) 4000000

Two coherent sources separated by distance d are radiating in phase having wavelength l. A detector moves in a big circle around the  two sources in the plane of the two sources. The angular position of n = 4 interference maxima is given as

(a)

(b)

(c)

(d)

1 Volt = _____________ style-type: lower- alpha;”>

The half-life period and the mean life period of a radioactive element are denoted respectively by T_h and T_m Then?

What happens when a glass rod is rubbed with silk?

Assertion : Ultraviolet radiation are of higher frequency waves are dangerous to human being.

Reason    : Ultraviolet radiation are absorbed by the atmosphere

(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.