Physics - Study Mode

[#456] Speed of sound is maximum in which among the following?
Correct Answer

(D) Solids

Explanation

Solution: We know that, in solids all the particles are packed together and hence sound can travel from one to one very fast. Hence, speed of sound is maximum in solids and decreases from solids to liquids and liquids to gases. Sound can't travel through vacuum.

[#457] The ringing of an electric bell in an enclosed evacuated glass bell jar is not heard outside because
Correct Answer

(D) There is no air or any other gas in the bell jar

Explanation

Solution: The ringing of an electric bell in an enclosed evacuated glass bell jar is not heard outside because there is no air or any other gas in the bell jar.

[#458] What is the full form of "RADAR" ?
Correct Answer

(A) Radio Detecting and Ranging

Explanation

Solution: Radio Detecting and Ranging is the full form of "RADAR".

[#459] Find the power of a convex lens if the image formed is at a distance of 25 cm from the lens when the object is placed on the other side of the lens at 12 cm from the optical centre?
Correct Answer

(B) 12.33 diopters

[#460] Find the power of a convex lens if the image formed is at a distance of 16 cm from the lens when the object is placed on the other side of the lens at 20 cm from the optical centre?
Correct Answer

(D) 11.25 diopters