Nuclei — Physics STD 12 Science — Question

The transfer ratio of a transistor is 50. The input resistance of the transistor when used in the common-emitter configuration is 1 KW. The peak value for an A.C input voltage of 0.01 V peak is

(a) 100 mA

(b) 0.01 mA

(c) 0.25 mA

(d) 500 mA

Neutrino is a particle, which is

(a) Charged and has spin	(b) Charged and has no spin
(c) Charge less and has spin	(d) Charge less and has no spin

Light with an energy flux of 20W/cm² falls on a non-reflecting surface at normal incidence. If the surface has an area of 30cm². the total momentum delivered (for complete absorption) during 30 minutes is:

If an electron enters a magnetic field with its velocity pointing in the same direction as the magnetic field, then

(a) The electron will turn to its right

(b) The electron will turn to its left

(c) The velocity of the electron will increase

(d) The velocity of the electron will remain unchanged

Three capacitors of 2.0, 3.0  and  6.0 μF are connected in series to a  10 V  source. The charge on the 3.0 μF  capacitor is

(a) 5 μC

(b) 10 μC

(c) 12 μC

(d) 15 μC

Find out the e.m.f. produced when the current changes from 0 to 1 A in 10 second, given L = 10 mH

(a) 1 V

(b) 1 mV

(c) 1 mV

(d) 0.1 V

If the energy of a photon corresponding to a wavelength of 6000 Å is 3.32 , the photon energy for a wavelength of 4000 Å will be

(a) 1.4 eV

(b) 4.9 eV

(c) 3.1 eV

(d) 1.6 eV

A charged particle oscillates about its mean equilibrium position with a frequency of 109 Hz. The frequency of electromagnetic waves produced by the oscillator is:

In reverse biasing:

Activity of radioactive element decreased to one third of original activity  in 9 years. After further 9 years, its activity will be

(a)

(b)

(c) /9

(d)