Semiconductor Electronic: Material, Devices And Simple Circuits — Physics STD 12 Science — Question

Light appears to travel in straight lines since

(a) It is not absorbed by the atmosphere

(b) It is reflected by the atmosphere

(c) Its wavelength is very small

(d) Its velocity is very large

In Boolean algebra A.B=Y implies the:

A source voltage of 8V drives the diode in fig. through a current-limiting resistor of 100 ohm. Then the magnitude of the slope load line on the V-I characteristics of the diode is

(a)  0.01

(b) 100

(c) 0.08

(d) 12.5

Two plane mirrors are at right angles to each other. A man stands between them and combs his hair with his right hand. In how many of the images will he be seen using his right hand

(a) None

(b) 1

(c) 2

(d) 3

The decay constant of a radioactive element is 1.5   per second. Its mean life in seconds will be

(a) 1.5

(b) 4.62

(c) 6.67

(d) 10.35

Why is the Wheatstone bridge better than the other methods of measuring resistances?

A pair of adjacent coils has a mutual inductance of 1.5 H. If the current in one coil changes from 0 to 20 A in 0.5 s, change of flux linkage with the other coil is

Two electric charges 12μC and -6 μC  are placed 20 cm apart in air. There will be a point P on the line joining these charges and outside the region between them, at which the electric potential is zero. The distance of P from -6 μC  charge is

(a) 0.10 m

(b) 0.15 m

(c) 0.20 m

(d) 0.25 m

Figure represents the graph of photo current I versus applied voltage (V). The maximum energy of the emitted photoelectrons is

(a) 2eV

(b) 4 eV

(c) 0 eV

(d) 4 J

The wiring of a house has resistance 6Ω A 100 W bulb is glowing. If a geyser of 1000 W is switched on, the change in potential drop across the bulb is nearly

(a) Nil

(b) 23 V

(c) 32 V

(d) 12 V