Physics important MCQs for all competitive exams

In this article Physics important MCQ’s for all competitive exams, we will discuss some important MCQ’S of physics for all competitive exams on graduation level.

Part A

Q.1 The input impedance of a transistor is-

(1) High

(2) low

(3) Very high

(4) Almost zero

Q.2 The value of α (common base current gain) of transistor is…

(1) More than 1

(2) Less than 1

(3) 1

(4) None of the above

Amswer: Less than 1

Q.3 The output impedance of a transistor is-

(1) High

(2) Zero

(3) Low

(4) Very low

Q.4 The relation between β and α is-

(1) β= 1/(1-α)

(2) β= (1- α)/α

(3) β= α/(1−α)

(4) β= α/(1+α)

Q.5 The input impedance of a transistor connected in… arrangement is the hightest

(1) Common Emitter

(2) Common collector

(3) Common Base

(4) None of the above

Part B

Q.6 The output impedance of a transistor connected in… arrangement is the highest-

(1) Common Emitter

(2) Common collector

(3) Common Base

(4) None of the above

Q.7 The output impedance of a transistor connected in… arrangement is the lowest.

(1) Common emitter

(2) Common collector

(3) Common Base

(4) None of the above

Q.8 The phase difference between the input and output voltages in a common base arrangement-

(1) 180⁰

(2) 90⁰

(3) 270⁰

(4) 0⁰

Q.9 The phase difference between the input and output voltages in a common collector arrangement is…

(1) 180⁰

(2) 90⁰

(3) 270⁰

(4) 0⁰

Q.10 The phase difference between the input and output voltages in a common emitter arrangement is-

(1) 180⁰

(2) 90⁰

(3) 270⁰

(4) 0⁰

Part C

Q.11 The voltage gain in a transistor connected in arrangement is the highest

(1) Common Base

(2) Common collector

(3) Common emitter

(4) None of the above

Q.12 As the temperature of a transistor goes up, The base-emitter resistance-

(1) Decreases

(2) Increases

(3) Remain the same

(4) None of the above

Q.13 The voltage of α is 0.9 then value of β Is…

(1) 0.9

(2) 9

(3) 900

(4) 90

Q.14 In a transistor, signal is traffeerred from a… circuit

(1) High resistance to low resistance

(2) Low resistance to high resistance

(3) High resistance to high resistance

(4) Low resistance to low resistance

Answer: Low resistance to high resistance ( because input is low and output is very high)

Q.15 A heat sink is generally used with a transistor to…

(1) Increase the forward current

(2) decrease the forward current

(3) compensate for excessive doping

(4) prevent excessive temperature rise

Part D

Q.16 The Collector-base junction in a transistor in active mode…

(1) Forward bias

(2) Reverse bias

(3) Low resistance

(4) None of the above

Q.17 The emitter-base junction in a transistor in active mode…

(1) F

(2) R

(3) L

(4) N

Q.18 A transistor can work in…mode

(1) Active

(2) Saturation

(3) Cut-off

(4) Reverse

(5) All of the above

Q.19 A transistor is saturation mode, E-B junction is… Bias and C.B junction is…Bias

(1) Forward, reverse

(2) Forward, forward

(3) Reverse, forward

(4) Reverse, reverse

Q.20 Transistor operator in cut-offand saturation. Act like a…

(1) linear amplitude

(2) Switch

(3) Variable capacitor

(4) variable resistor

Part E

Q.21 Tesla is the unit of

(1) Field strength

(2) Induction

(3) Flux density

(4) flux

Q.22 A magnetic field exists around

(1) Iron

(2) Copper

(3) Aluminium

(4) Moving charges

Q.23 The ratio of intensity of magnetization to the  mangetization force is known as

(1) Flux density

(2) Susceptibility

(3) Relative permeability

(4) None of the above

Q.24 Substances which have permeability less than the permeability of free space are known as

(1) Ferromagnetic

(2) paramagnetic

(3) diamagnetic

(4) bipolar

Q.25 Susceptibility is positive for

(1) Non-magnetic substances

(2) Diamagnetic substances

(3) Ferromagnetic substances

(4) None of the above

Q.26 A permanent magnet

(1) Attracts some substances and repels other

(2) Attracts all paramagnetic substances and repels others

(3) Attracts only ferromagnetic substances

(4) Attracts ferromagnetic substances and repels all others

Answer:- Attracts some substances and repels other