Magnetism and Matter — Physics STD 12 Science — Question

The breakdown in a reverse biased p-n junction diode is more likely to occur due to:

A magnet oscillating in a horizontal plane has a time period of 2 second at a place where the angle of dip is 30^o and 3 seconds at another place where the angle of dip is 60^o. The ratio of resultant magnetic fields at the two places is

(a)

(b)

(c)

(d)

A metal plate gets heated, when cathode rays strike against, it due to

(a) Kinetic energy of cathode rays	(b) Potential energy of cathode rays
(c) Linear velocity of cathode rays	(d) Angular velocity of cathode rays

Young's experiment establishes that

(a) Light consists of waves

(b) Light consists of particles

(c) Light consists of neither particles nor waves

(d) Light consists of both particles and waves

An electric fan and a heater are marked as 100 watt, 220 volt and 1000 watt, 220 volt respectively. The resistance of the heater is

(a) Zero	(b) Greater than that of the fan
(c) Less than that of the fan	(d) Equal to that of the fan

Current provided by a battery is maximum when

(a) Internal resistance equal to external resistance

(b) Internal resistance is greater than external resistance

(c) Internal resistance is less than external resistance

(d) None of these

The ratio of secondary to primary turns is 9 : 4. If power input is P, what will be the ratio of power output (neglect all losses) to power input

(a) 4 : 9

(b) 9 : 4

(c) 5 : 4

(d) 1 : 1

A metal plate is getting heated. It can be because:

In the circuit element given here, if the potential at point B, V_B = 0, then the potentials of A and D are given as

(a)	(b)
(c)	(d)