Physics - Study Mode

[#411] The type of mirrors used in the headlamp of cars is
Correct Answer

(A) Parabolic concave

Explanation

Solution: A concave mirror is used in the headlight of a car. The reason being that a concave mirror is a converging mirror as opposed to a convex mirror which is a diverging mirror. In headlights the bulb is kept at the focus of the mirror.

[#412] Shaving mirror is
Correct Answer

(B) Concave

Explanation

Solution: A shaving mirror gives an enlarged image. The mirror is concave. You must have your face within the focal length of the mirror, to get an upright and enlarged image.

[#413] What changes will happen to a bowl of ice and water kept at exactly zero degree Celsius ?
Correct Answer

(C) No change will happen

Explanation

Solution: Fresh water cooled to zero degree Celsius and subjected to additional loss of heat energy normally will freeze. A mixture of fresh water and ice has an equilibrium temperature of zero degree Celsius. Adding heat to the mixture causes ice to melt whereas removing heat causes water to freeze. So, no change will happen.

[#414] At what temperature do the Fahrenheit and Celsius scales give the same reading?
Correct Answer

(C) -40 degreees

Explanation

Solution: The temperature when both the Celsius and Fahrenheit scales are the same is -40 degrees.

[#415] The temperature of a liquid is 32° F. What is its temperature in Celsius scale?
Correct Answer

(B) 0° C

Explanation

Solution: The Fahrenheit scale defines the freezing point of water as 32°F and the boiling point as 212°F. The Celsius scale sets the freezing point and boiling point of water at 0°C and 100°C respectively.