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

In image formation from spherical mirrors, only paraxial rays are considered because they:

1. Are easy to handle geometrically.
2. Contain most of the intensity of the incident light.
3. Form nearly a point image of a point source.
4. Show minimum dispersion effect.

What will be the angular momentum of a electron, if energy of this electron in H-atom is 1.5eV (in J-sec)

(a) 1.05

(b) 2.1

(c) 3.15

(d) -2.1

In circular coil, when no. of turns is doubled and resistance becomes   of initial, then inductance becomes

(a) 4 times

(b) 2 times

(c) 8 times

(d) No change

A 20cm long capillary tube is dipped in water. The water rises up to 8cm. If the entire arrangement is put in a freely falling elevator, the length of water column in the capillary tube will be:

1. 8cm
2. 6cm
3. 10cm
4. 20cm

A solenoid has an inductance of 60 henrys and a resistance of 30 ohms. If it is connected to a 100 volt battery, how long will it take for the current to reach   of its final value

(a) 1 second

(b) 2 seconds

(c) e seconds

(d) 2e seconds

In a primary coil 5A current is flowing on 220 volts. In the secondary coil 2200V voltage produces. Then ratio of number of turns in secondary coil and primary coil will be

(a) 1 : 10

(b) 10 : 1

(c) 1 : 1

(d) 11 : 1

The electrical circuits used to get smooth d.c. output from a rectifier circuit is called

(a) Filter

(b) Amplifier

(c) Full wave rectifier

(d) Oscillator

ike magnetic force ______ each other.

Intensity of light depends upon

(a) Velocity

(b) Wavelength

(c) Amplitude

(d) Frequency