Physics - Study Mode

[#406] Intensity of sound has
Correct Answer

(A) an object existence

Explanation

Solution: Intensity of sound has an object existence.

[#407] Rain is falling vertically downwards. To a man running east-wards, the rain will appear to be coming from
Correct Answer

(A) east

Explanation

Solution: With vertical, the relative velocity will be inclined and appear to be coming from east.So the rain will appear to be coming from east.

[#408] An aeroplane is flying horizontally with a velocity of 600 km/h and at a height of 1960 m. When it is vertically at a point A on the ground a bomb is released from it. The bomb strikes the ground at point B. The distance AB is
Correct Answer

(C) 3.33 km

[#409] An optically plane surface reflects a beam of light
Correct Answer

(A) As a parallel beam in one direction

Explanation

Solution: An optically plane surface reflects a beam of light as a parallel beam in one direction. The set of incident rays are reflected as a set of rays. This type of reflection of a set of rays is called Specular Reflection.

[#410] The focal length of a concave mirror with a radius of curvature of 20.0 cm is :
Correct Answer

(C) 10 cm

Explanation

Solution: Let us assume f is focal length R is radius of curvature According to the formula R = 2f f = R/2 = 20/2 = 10 cm