Physics interview questions – page 3

On the left side of the PN junction

1. the acceptor atoms become positive ions
2. the donor atoms become negative ions
3. the donor atoms become positive ions
4. the acceptor atoms become negative ions

On the right side of the PN junction

1. the donor atoms become positive ions
2. the donor atoms become negative ions
3. the acceptor atoms become negative ions
4. the acceptor atoms become positive ions

Multimeter measures

1. resistance
2. current
3. voltage
4. all the above

The moving coil galvanometer is connected into an ammeter by connecting

1. a low resistance in series
2. a high resistance in series
3. a low resistance in parallel
4. a high resistance in parallel

The alternating emf induced in the coil varies

1. periodically in both magnitude and direction
2. randomly in both magnitude and direction
3. periodically in direction only
4. periodically in magnitude only

An AC generator converts _____ into electrical energy.

1. magnetic energy
2. mechanical energy
3. sound energy
4. vibrational energy

The part of the AC generator that passes the current from the coil to the external circuit is

1. slip rings
2. split rings
3. brushes
4. field magnet

In an induction furnace, high temperature is produced by

1. the burning of the fuel
2. using transformer
3. generating eddy currents
4. none of these

Transformer works on

1. AC more effectively than DC
2. AC only
3. DC only
4. Both AC and DC

Who discovered the production of induced emf by the effect of magnetic field?

1. Fleming
2. Michael Faraday
3. Christian Oersted
4. Christian Huygens

Which of the following components is not used in AC generator?

1. Armature
2. Brushes
3. Slip rings
4. Split rings

The device used for controlling current in an AC circuit is

1. Choke coil
2. Transformer
3. Starter
4. Slip ring

_____ is a forward biased PN junction diode which emits visible light when energized.

1. Zener diode
2. LCD
3. LED
4. None of the above

The central region of the output characteristic curve is called

1. active region
2. breakdown region
3. cutoff region
4. saturation region

Electrons and holes can be generated in a semiconductor crystal with

1. heat energy or light energy
2. heat energy and light energy
3. light energy
4. heat energy

Who discovered that a current carrying conductor is associated with a magnetic field?

1. Christian Oersted
2. Christian Huygens
3. Fleming
4. Michael Faraday

Iron loss is otherwise called

1. Eddy current loss
2. Flux loss
3. Copper loss
4. Hysteresis loss

Eddy current was discovered by

1. Foucault
2. Faraday
3. Oersted
4. Lenz

The armature of AC generator is wound on

1. copper frame
2. soft iron core
3. wood
4. bakelite

The self inductance of a straight conductor is

1. zero
2. infinity
3. very large
4. very small

Power from all power stations are fed to the

1. collecting station
2. pycons
3. transformer
4. grid

The property of a coil which enables to produce an opposing induced emf in it when the current in

1. static induction
2. self induction
3. mutually induction
4. none of the above

Electromagnetic induction is used in

1. choke coil
2. ac generator
3. room heater
4. transformer

The power loss is less in transmission lines when

1. voltage is less but current is more
2. voltage is more but current is less
3. both voltage and current are more
4. voltage is less but current is more

_____ is called AVO meter.

1. Multimeter
2. Galvanometer
3. Voltmeter
4. Ammeter

_____ are used for instrument displays, calculators and digital watches.

1. Light emitting diodes
2. PN Junction diodes
3. Zener diodes
4. All the above

Pick out the pentavalent atom from the following.

1. Antimony
2. Aluminium
3. Boron
4. Indium

Sinusoidal oscillator generate

1. sine wave
2. cosine wave
3. square wave
4. all the above

Oscillators are classified according to the range of frequency as

1. audio and high frequency oscillators
2. high and ultra high frequency oscillators
3. audio and radio frequency oscillators
4. sinusoidal and non-sinusoidal oscillators

Number of electrons in silicon atom are

1. 4
2. 8
3. 14
4. 20