Physics questions and answers

Physics Questions and Answers

If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.

151.

A bar magnet is divided into two pieces, which of the following statement is correct?

A.

two new magnets are created

B.

the magnetic field of each separate piece becomes stronger

C.

the electric field is created

D.

the bar magnet is demagnetized

Correct answer is A

When it is cut into two, the two cut pieces will have their own north and south poles.

152.

Which of these is a derived unit?

A.

Kilogram

B.

Metre

C.

Newton

D.

Second

Correct answer is C

Examples of Fundamental Quantities ; Mass, kilogram, kg ; Electric Current, ampere, A ; Temperature, kelvin, K ; Amount of Substance, mole, Mol.

153.

In which of the following situations is friction not useful?

A.

Operation of a grinding machine

B.

Walking

C.

Application of brakes

D.

Moving piston in a sleeve

Correct answer is D

 friction, force that resists the sliding or rolling of one solid object over another.

Examples of friction in our daily life

  • Driving of a a vehicle on a surface.
  • Applying brakes to stop a moving vehicle.
  • Skating.
  • Walking on the road.

154.

The basic principle of operation of a beam balance is-----------------

A.

Hooke's law

B.

Archimedes principle

C.

law of flotation

D.

principle of moments

Correct answer is D

Hooke's Law states that the extension of a spring is proportional to the load that is applied to it. A variety of materials obey this law as long as the load does not exceed the material's elastic limit.

Archimede's Principle states that a body immersed in a fluid experiences an upthrust equal to the weight of the fluid displaced, and this is fundamental to the equilibrium of a body floating in still water.

When a body floats in a liquid, the weight of the liquid displaced by its immersed part is equal to the total weight of the body. This is the law of floatation.

The Principle of Moments states that when a body is balanced, the total clockwise moment about a point equals the total anticlockwise moment about the same point.

155.

Using venier calipers, which of the following readings gives the correct measurement for the length of a rod?

A.

4.1 cm

B.

4.13cm

C.

125 cm

D.

1254 cm

Correct answer is B

Vernier calipers commonly used in industry provide a precision to 0.01 mm (10 micrometres), or 0.01cm or one thousandth of an inch.

 Usually, it is the total length of the main scale. Vernier calipers, generally, have a range of 300 mm

300 millimeters equal 30.0 centimeters (300mm = 30.0cm).

156.

The viscosity of a fluid depends on the following factors except the?

A.

relative motion between the layers of the fluid

B.

nature of the material of the fluid

C.

surface area of the fluid in contact

D.

normal reaction in the fluid

Correct answer is D

The viscosity of a material is affected by temperature, pressure, nature of fluid, velocity gradient

157.

Molecules move in random motion within a liquid. The total internal energy of the liquid depends on all of the following except its?

A.

temperature

B.

mass

C.

specific heat capacity

D.

melting point

Correct answer is D

Internal energy is affected by factors such as pressure, volume, and temperature.

All of the variables in this list are state functions. Mass, volume, pressure, temperature, density, and entropy are all examples of state functions.

158.

A small object of mass 50 g is released from a point A. Determine the velocity of the object when it reaches a point B, a vertical distance of 30m below A. [g = 10 ms\(^{-2}\)

A.

1.5 ms\(^{-1}\)

B.

6.0 m s\(^{-1}\)

C.

17.3 m s\(^{-1}\)

D.

24.5 m s\(^{-1}\)

Correct answer is D

v = ?, u = 0, a = 10, s = 30

V² = U²+2as
V² = 0 + 2 * 10 * 30
V² = 0 + 600
V = √600
V = 24.5m/s 

159.

A quantity of water at 0 °C is heated to 30 °C. For each degree rise in temperature, its density will---------

A.

rise steadily

B.

fall steadily

C.

fall and then rises

D.

rise and then falls

Correct answer is D

When water is heated, the density rises and falls steadily, remember the anomalous expansion of water.

160.

The engine of a car provides a forward force of 1240 N and the total resistive force on the car is 800N. If the mass of the car is 1220 kg, determine the distance the car has to travel from the rest before acquiring a speed of 4 m s\(^{-1}\).

A.

44.0 m

B.

22.2 m

C.

11.1 m

D.

5.5 m

Correct answer is B

Acceleration[a] = \(\frac{[forward - resistive]force}{mass}\)

a = \(\frac{1240-800}{1220}\) → \(\frac{440-800}{1220}\)

a = 0.36m/s\(^2\),  v = 4m/s, s = ?

Second equation of motion:

s is distance
u is initial velocity
v is final velocity
a is acceleration

v\(^2\) = u\(^2\) + 2as

4\(^2\) = 0\(^2\) + 2 * 0.36 * s

16 =  0.72s 

22.2m = s


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