Practice MCQ Questions and answers on Physics-GK

41

The boiling point of water depends upon the

A) Atmospheric pressure B) Volume C) Density D) Mass

Discuss

Answer & Solution

Answer: Option A

Solution:

The boiling point of water depends upon the atmospheric pressure.

42

One bar is equal to

A) 10³ Pa B) 10⁶ Pa C) 10⁵ Pa D) 10⁴ Pa

Discuss

Answer & Solution

Answer: Option C

Solution:

One bar is equal to 10⁵ Pa.

43

Pressure Cooker cooks faster because

A) Boiling point decreases with rise of pressure B) It cooks the food at low pressure C) Higher temperature is attained for cooking D) The material of the cooker is a good conductor

Discuss

Answer & Solution

Answer: Option C

Solution:

Food is cooked more quickly in a pressure cooker because at the higher pressure (1 bar/15 psi), the boiling point of water rises from 100°C (212°F) to 121°C (250°F). Since less water or liquid has to be heated, the food reaches its cooking temperature faster.

44

In a particular system, the units of length, mass and time are chosen to be 10 cm, 10 g and 0.1 s respectively. The unit of force in this system will be equivalent to

A) 0.1 N B) 1 N C) 10 N D) 100 N

Discuss

Answer & Solution

Answer: Option A

Solution:

Mass = 10 g = 0.01 kg
Length = 10 cm = 0.1 m
Time = 0.1 s
Force = mass × length/ time ^2
= > Force = 0.01 × 0.1 × 0.1^-2 = 0.1 N

45

The weakest of all fundamental forces is

A) Gravitational force B) Electrostatic force C) Magnetic force D) Nuclear force

Discuss

Answer & Solution

Answer: Option A

Solution:

Gravitation is by far the weakest of the four interactions at the atomic scale, where electromagnetic interactions dominate.

46

The unit of force is a

A) Derived Unit B) Basic Unit C) Fundamental Unit D) None of the above

Discuss

Answer & Solution

Answer: Option A

Solution:

The unit of force is a derived unit.

47

Atmospheric pressure exerted on earth is due to

A) Gravitational pull B) Rotation of earth C) Revolution of earth D) Uneven heating of earth

Discuss

Answer & Solution

Answer: Option A

Solution:

Atmospheric pressure is caused by the gravitational attraction of the planet on the atmospheric gases above the surface, and is a function of the mass of the planet, the radius of the surface, and the amount and composition of the gases and their vertical distribution in the atmosphere.

48

What is the SI unit of Force?

A) Pascal B) Boyle C) Newton D) Watt

Discuss

Answer & Solution

Answer: Option C

Solution:

SI unit of force is Newton.

49

What measures Air pressure?

A) Barkometer B) Bolometer C) Spectrometer D) Barometer

Discuss

Answer & Solution

Answer: Option D

Solution:

Barometer measures air pressure.

50

The rice is cooked more quickly in a pressure cooker because

A) It is covered. B) Less quantity of water is used. C) None of these D) Water boils at a higher temperature under pressure.

Discuss

Answer & Solution

Answer: Option D

Solution:

Food is cooked more quickly in a pressure cooker because at the higher pressure (1 bar/15 psi), the boiling point of water rises from 100°C (212°F) to 121°C (250°F). The hotter steam is able to transmit its thermal energy to the food at around 4 times the rate of conventional boiling.