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.

71.

The diagram above illustrates the penetrating power of some types of radiation. X, Y and Z are likely

A.

X = α-particle; Y = γ-ray; Z = β-particle

B.

X = α-particle; Y = β-particle; Z = γ-ray

C.

X = γ-ray; Y = α-particle; Z = β-particle

D.

X = β-particle; Y = γ-ray; Z = α-particle

Correct answer is C

The penetrating power of alpha rays, beta rays, and gamma rays varies greatly. Alpha particles can be blocked by a few pieces of paper. Beta particles pass through paper but are stopped by aluminum foil. Gamma rays are the most difficult to stop and require concrete, lead, or other heavy shielding to block them.

Therefore, X = γ-ray; Y = α-particle; Z = β-particle

72.

The sensitivity of a thermometer is

A.

All of the above

B.

how quickly a temperature change can be detected

C.

the difference between the maximum and the minimum temperature

D.

the smallest temperature change that can be detected or measured

Correct answer is D

The sensitivity of a thermometer is defined as the smallest temperature change that can be detected or measured, NOT how quickly that temperature change can be detected.

In contrast, the difference between the maximum and the minimum temperature is the range of a thermometer

73.

An open-tube mercury manometer is used to measure the pressure in a gas tank. When the atmospheric pressure is 101,325 \(P_a\), what is the absolute pressure in \(P_a\) in the tank if the height of the mercury in the open tube is 25 cm higher. density of mercury = \(13600kg/m^3, g = 9.8m/s^2\)

A.

108,986 Pa

B.

165,238 Pa

C.

122,364 Pa

D.

134,645 Pa

Correct answer is D

density (ρ) = 13600 \(kgm^{-3}\); g =\(9.8 ms^{-2}\)

\(P_{atm}\) =101,325 Pa;  ρ=13600 \(kgm^{-3}\)


Pabs=\(P_{atm}\)+ρgh


⇒Pabs=101,325+13600 x 9.8 x 0.25
 

⇒Pabs=101,325+33320

⇒ Pabs=134,645Pa

74.

A beam of light travelling in water is incident on a glass which is immersed in the water. The incident beam makes an angle of \(40^o\) with the normal. Calculate the angle of refraction in the glass.

[Refractive index of water = 1.33, Refractive index of glass = 1.5]

A.

\(29.36^o\)

B.

\(25.37^o\)

C.

\(37.21^o\)

D.

\(34.75^o\)

Correct answer is D

\(n_1\)=1.33; \(n_2\)=1.5;  i=40°; r= ?

from snell's law:

\(n_1\) x sin i=\(n_2\)x sin r

⇒1.33 x sin 40°=1.5 x sin r

⇒sin r = 0.5700

⇒r = \(sin^{-1}\) (0.5700)

 ⇒ r = 34.75

 

 

 

75.

How much work is done against the gravitational force on a 3.0 kg object when it is carried from the ground floor to the roof of a building, a vertical climb of 240 m?

A.

7.2 kJ

B.

4.6 kJ

C.

6.8 kJ

D.

8.4 kJ

Correct answer is A

The work done against the gravitational force is calculated using the formula W = mgh, where m is the mass of the object, g is the acceleration due to gravity (approximately \(9.8 ms^2\) on Earth), and h is the height. Substituting the given values, we get W = 3.0 kg * \(9.8 m/s^2\) * 240 m = 7.2 kJ. Therefore, the correct answer is '7.2 kJ'.