MCQ
Specific resistance of a semiconductor on increasing temperature :
  • A
    increases
  • decreases
  • C
    remains unchanged
  • D
    first decreases and then increases

Answer

Correct option: B.
decreases
(b) - decreases

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

A wire of length 5 m and radius 1 mm has a resistance of 1 ohm. What length of the wire of the same material at the same temperature and of radius 2 mm will also have a resistance of 1 ohm

(a) 1.25 m

(b) 2.5 m

(c) 10 m  

(d) 20 m

Three bulbs of 40 W, 60 W, 100 W are arranged in series with 220 volt supply which bulb has minimum resistance

(a) 100 W

(b) 40 W

(c) 60 W  

(d) Equal in all bulbs

The angle of dip at the magnetic equator is

(a) 0°

(b) 45°

(c) 30°

(d) 90°

A solid sphere and a hollow sphere of the same material and of equal radii are heated to the same temperature:
  1. Both will emit equal amount of radiation per unit time in the biginning.
  2. Both will absorb equal amount of radiation from the surrounding in the biginning.
  3. The initial rate of cooling $\Big(\frac{\text{dT}}{\text{dt}}\Big)$ will be the same for the two spheres.
  4. The two spheres will have equal temperatures at any instant.

The magnetic field near a current carrying conductor is given by

(a) Coulomb’s law

(b) Lenz’ law

(c) Biot-savart’s law

(d) Kirchoff’s law

In a situation the contact force by a rough horizontal surface on a body placed on it has constant magnitude. If the angle between this force and the vertical is decreased, the frictional force between the surface and the body will:
  1. Increase.
  2. Decrease.
  3. Remain the saint.
  4. May increase or decrease.

A coil takes 15 min to boil a certain amount of water, another coil takes 20 min for the same process. Time taken to boil the same amount of water when both coil are connected in series

(a) 5 min

(b) 8.6 min

(c) 35 min

(d) 30 min

The magnetic field lines due to a bar magnet are correctly shown in

(a)

(b)

(c)

(d)

Function of rectifier is

(a) To convert ac into dc

(b) To convert dc into ac

(c) Both (a) and (b)

(d) None of these

Conditions of diffraction is

(a)

(b)  

(c)  

(d) None of these