MODEL PAPER 3 — Physics STD 12 Science — Question

The capacity of any conductor is :

The inductance of a solenoid 0.5 m long of cross-sectional area 20 cm² and with 500 turns is

(a) 12.5 mH

(b) 1.25 mH

(c) 15.0 mH

(d) 0.12 mH

Wave nature of light follows because

(a) Light rays travel in a straight line

(b) Light exhibits the phenomena of reflection and refraction

(c) Light exhibits the phenomenon of interference

(d) Light causes the phenomenon of photoelectric effect

In the given figure, which of the diodes are forward biased ?

1.2.3.  4. 5.

(a) 1, 2, 3

(b) 2, 4, 5

(c) 1, 3, 4

(d) 2, 3, 4

In Young's double slit experiment, the phase difference between the light waves reaching third bright fringe from the central fringe will be (λ =6000 Å )

(a) Zero

(b) 2π

(c) 4 π

(d) 6 π

3 A of current is flowing in a linear conductor having a length of 40 cm. The conductor is placed in a magnetic field of strength 500 gauss and makes an angle of 30° with the direction of the field. It experiences a force of magnitude

(a) 3

(b) 3

(c) 3

(d) 3

Which of the following cannot be polarized?

Atomic number (Z) of a neutral atom and mass number (A) of an atom are equal to:(Here n = number of neutrons and p = number of protons):

In the Millikan's experiment, the distance between two horizontal plates is 2.5 cm and the potential difference applied is 250 V. The electric field between the plates will be

(a) 900 V/m

(b) 10000 V/m

(c) 625  V/m

(d) 6250 V/m

A transistor is used as an amplifier in CB mode with a load resistance of 5 k W the current gain of amplifier is 0.98 and the input resistance is 70 W, the voltage gain and power gain respectively are

(a) 70, 68.6

(b) 80, 75.6

(c) 60, 66.6

(d) 90, 96.6