physics

Question 1

What is the SI unit for measuring intensity of ‘sound or ‘Noise™?

Answer 1

Decibel

Question 2

What principle/law explains the working of the hydraulic brakes in automobiles?

Answer 2

Pascal’s law

Question 3

Name the process of production of energy in the Sun

Answer 3

Nuclear fusion

Question 4

The type of mirror used in automobiles to see the
traffic on the rear side is

Answer 4

Convex

Question 5

The sun heats the earth through:

Answer 5

Radiation

Question 6

Which one of the following has the highest value of
specific heat and used in a “hot water bag” and “car
radiator”?

Answer 6

Water

Question 7

At what temperature (in degree Celsius), the numerical values on Celsius and Fahrenheit scales become equal?

Answer 7

-40

Question 8

Instrument used to measure the force, velocity and speed of the wind is

Answer 8

Anemometer

Question 9

Which animals use ultrasonic sound to catch their
prey and avoid obstacles?

Answer 9

Bats

Question 10

The oil in the wick of an oil lamp rises up due to:

Answer 10

Capillary action

Question 11

What type of lens is used to correct vision of a person suffering from Myopia or near sightedness or ‘Short- sight?

Answer 11

Concave lens

Question 12

lens [#R-5, TCS|
What is the SI unit of temperature?

Answer 12

Kelvin

Question 13

dynamo is used to convert

Answer 13

:- Mechanical energy into electrical energy

Question 14

Name the device that measures the distance travelled by a vehicle

Answer 14

Odometer

Question 15

A is an electrical device that converts alternating current to direct current which flows only in one direction.

Answer 15

rectifier

Question 16

Twinkling of stars is mainly due to which phenomena?

Answer 16

Refraction of light by atmosphere

Question 17

The blue colour of sky is due to

Answer 17

scattering of shorter wavelengths of sunlight in
the atmosphere

Question 18

Fiber-optic cable used in communication, works on the principle of

Answer 18

total internal reflection of light

Question 19

Ozone layer above the surface of Earth provides a
shield against

Answer 19

Ultra-violet rays

Question 20

Calculate the time period (in seconds) of asound wave of wavelength 2m travelling with a speed of 250 m/s.

Answer 20

0.008

Question 21

Calculate the pressure (in Pa) if a thrust of 750 N is applied to an area of 5 m2.

Answer 21

150pa

Question 22

Find the acceleration (in m/s?) produced in a body of mass 10 kg when a force of 20 N is applied on it

Answer 22

2

Question 23

The audible range of sound for an average adult human
being is

Answer 23

20 Hz - 20000 Hz

Question 24

What is the resistance (in Q) of an electrical compo- nent if a current of 0.4 A passes through it on application of 12 V of potential difference across it?

Answer 24

30

Question 25

A body of mass 3 kg accelerates from 10 m/s to 20 m/s in 5 seconds due to the application of a force on it. Calculate the magnitude of this force (in N).

Answer 25

6

Question 26

Due to an acceleration of 1 m/s? the velocity of a body increases from 15 m/s to 20 m/s in a certain period. Find the displacement (in m) of the body in that peri- od.

Answer 26

87.5

Question 27

The splitting of white light into its constituent colours. by a triangular prism is called

Answer 27

Dispersion of light

Question 28

A light year is a measure of

Answer 28

Distance

Question 29

is a scalar quantity.

Answer 29

Electric current / Speed / Powe

Question 30

Hertz is the SI unit of

Answer 30

Frequency

Question 31

A is a safety device which limit the current, prevents damages to electrical circuits and possible fires

Answer 31

Fuse

Question 32

has the same dimension as that of linear mo- mentum?

Answer 32

Impulse

Question 33

The Newton’s First Law is also called as

Answer 33

Law of inertia

Question 34

The SI unit of acceleration is

Answer 34

m/s2

Question 35

Quantitatively, the inertia of an object is measured by its

Answer 35

Mass

Question 36

Which electromagnetic radiation is used for artificial satellite communication?

Answer 36

Microwave

Question 37

What is the SI unit for electrical resistance?

Answer 37

Ohm

Question 38

What is the SI unit of pressure?

Answer 38

Pascal

Question 39

Speed of sound in air is unaffected by change in:

Answer 39

Pressure

Question 40

The reason for a swimming pool to appear less deep than the actual depth is

Answer 40

Refraction

Question 41

Hygrometer is a device which is used to measure

Answer 41

Relative humidity

Question 42

In 1662, ____________ formulated a fundamental law in gas dynamics named _____________ , which concluded that for a given mass of gas at constant temperature, the volume of the gas varies inversely with its pressure. This law, expressed through the equation P1V1 = P2V2, demonstrates that when a gas is compressed in an enclosed space, its volume decreases while the pressure it exerts on the container increases.

Answer 42

Robert Boyle, Boyle’s Law

Question 43

Which of the metals has the maximum thermal/elec- trical conductivity?

Answer 43

Silver

Question 44

The instrument which uses sound waves to measure the depth of oceans is

Answer 44

Sonar

Question 45

In which of the following mediums, speed of the sound will be maximum?

Answer 45

Steel

Question 46

A solid needle placed horizontally on the surface of the water floats due to

Answer 46

surface tension of water

Question 47

During ________________ ‘motion of an object along a straight line, the velocity remains constant with time.

Answer 47

Uniform

Question 48

Find the work done (in J) when a charge of 24 C moves across a potential difference of 6 V.

Answer 48

144 (W=V*Q — 6*24 — 144)

Question 49

Find the acceleration (in m/s?) of a body which accel- erates from 10 m/s to 20 m/s in 4 seconds.

Answer 49

2.5

Question 50

The sound waves having frequencies less than ___________ Hz are called infrasonic waves.

Answer 50

20

Question 51

What is the value of the Least Distance of Distinct vi- sion (in cm) for a normal human being?

Answer 51

25

Question 52

A Sonar of a ship sends sounds waves of speed 1500 m/s. These waves are reflected back by the ocean floor in 5 seconds. Find the depth (in m) of the ocean floor.

Answer 52

3750

Question 53

Find the potential energy gained by a body of mass 60 kg, if it is raised by 12 m.

Answer 53

7200 The potential energy (PE) gained by a body of mass (m) raised to a height (h) is given by the formula: PE = m * g * h

Question 54

How many watts are there in a horsepower?

Answer 54

746 watts

Question 55

What is the effective resistance (in Q) of two resistors 12 Q and 24 Q connected in parallel?

Answer 55

8

Question 56

What is the heat generated (in J) in a heating element of resistance 900 Q when a current of 0.3 A passes through it for 10 seconds?

Answer 56

810 H = I² * R * t

Question 57

The instrument used to measure either direct or alter- nating electric current in amperes is called:

Answer 57

ammeter

Question 58

What is the SI unit of electric current

Answer 58

Ampere

Question 59

“Parsec” is the unit measurement of

Answer 59

Astronomical distance

Question 60

Which scientific instrument is used to measure atmospheric pressure?

Answer 60

Barometer

Question 61

What is the SI unit for measuring the luminous inten- sity

Answer 61

Candela

Question 62

When milk is churned, the cream separates from it due to:

Answer 62

Centrifugal force

Question 63

Which lens always forms a virtual, erect and dimin- ished image?

Answer 63

Concave

Question 64

Which mirror is used by doctors for examining eyes, ears, nose, throat and teeth?

Answer 64

Concave mirror

Question 65

On the basis of which phenomenon does the Jet Engine work?

Answer 65

Conservation of Linear Momentum

Question 66

What is the SI unit of lens capacity?

Answer 66

Dioptre

Question 67

Kilowatt hour (kWh) represents the unit of

Answer 67

Energy

Question 68

Which is the highest-frequency (minimum wavelength) electromagnetic waves?

Answer 68

Gamma Rays

Question 69

Which is a bad Thermal Conductor (good insulator)

Answer 69

Glass

Question 70

A Fuse wire is characterised by

Answer 70

High resistance and low melting point

Question 71

Amount of water vapour (moisture in air) in the atmosphere is measured in terms of

Answer 71

Humidity

Question 72

Which is the first known instrument to measure the humidity of air or gas, built by Leonardo da Vinci around 1400?

Answer 72

Hygrometer

Question 73

Rainbows are produced when sunlight:

Answer 73

Incident on rain drops hanging in the atmosphere is dispersed after suffering refraction and internal reflection.

Question 74

A metal plate with a circular hole at the centre is heated. What will happen to the area of the hole?

Answer 74

Increases

Question 75

The device which converts sound energy into electrical energy is called

Answer 75

Microphone

Question 76

The phenomenon of change in direction of light when it passes from one medium to another is called

Answer 76

Refraction

Question 77

The colour of the clear sky is blue due to the phenomenon of:

Answer 77

scattering of light

Question 78

The “laws of vibrating string” can be studied by

Answer 78

Sonometer

Question 79

Heat flows as a result of difference of

Answer 79

Temperature

Question 80

The colours of stars depend on their

Answer 80

Temperature

Question 81

The first law of thermodynamics is simply the case of

Answer 81

The law of conservation of energy

Question 82

The filament of electric bulb is made up of

Answer 82

Tungsten

Question 83

A small drop of oil spreads over water because:

Answer 83

water has a higher surface tension

Question 84

A bullet of mass 10gm is fired with a velocity of 40 m/s from a gun of mass 8 kg. Find the recoil velocity (in m/s) of the gun.

Answer 84

0.05 (0.01 * 40/8)

Question 85

1 Micron is equal to

Answer 85

10^-6m

Question 86

Escape velocity at the earth’s surface is

Answer 86

11.2 km/s

Question 87

Find the kinetic energy (in J) possessed by a body of mass 10 kg moving with a velocity of 5 m/s.

Answer 87

125 KE = 1/2 * m * v^2

Question 88

What is the heat released by a heating filament rated 24 W when it is kept on for 6 seconds?

Answer 88

Heat (Q) = Power (P) * Time (t) 144

Question 89

68 degree Fahrenheit is equal to how many degrees Centigrade?

Answer 89

Celsius = (Fahrenheit - 32) * 5/9   20

Question 90

Find the current (in A) when a charge of 500 Coulomb flows in 25 seconds.

Answer 90

20

Question 91

A body of mass 8 kg is moving with a velocity of 4m/s, find its momentum.

Answer 91

32

Question 92

Water has maximum density of 1 g/cc at

Answer 92

4 degree celsius

Question 93

Find the resistance (in mega ) of awire of length 20m, cross sectional area 1 cm? and made of a material of resistivity 200 Qm.

Answer 93

R = ρ * L / A 40

Question 94

The angle in which a cricket ball should be hit to travel maximum horizontal distance is:

Answer 94

45° with horizontal

Question 95

If the acceleration due to gravity on the surface of earth is g, then the acceleration due to gravity on the surface of a planet whose mass is same as that of earth and radius is half as that of earth is _________

Answer 95

The acceleration due to gravity (g) is given by the formula: g = GM / r^2 4g

Question 96

What is value of G (gravitational constant) in F =Gm1m2/r?

Answer 96

6.672 x10^-11 N m2 kg ^-2

Question 97

Calculate the frequency (in Hz) of a sound wave of wavelength 5 m travelling with a speed of 360 m/s.

Answer 97

72

Question 98

What is the power rating (in W) of a bulb if a current of 0.3 A passes through on application of 240 V of poten- tial difference across its terminals?

Answer 98

72 Power = (Current)^2 * Resistance v=I R

Question 99

A body is initially moving with a velocity of 10 m/s It undergoes an acceleration of 2 m/s for 5 seconds Find the displacement (in m) of this body in these 5 seconds.

Answer 99

75

Question 100

A galvanometer can be converted to a voltmeter by connecting

Answer 100

high resistance in series