A submarine emits a sonar pulse, which returns from an underwater cliff in 1.02 s.

(a) ultrasonic waves

SONAR is SOund Navigation And Ranging. It is a technique used to measure the depth of the sea, locate the sunken ships or icebergs and submarines.

Roots of pulses (leguminous plants) have a symbiotic association with a bacterium called Rhizobium which fixes nitrogen. Hence, farmers need not use nitrogenous fertilizers

(a) swim easily in water.

Let the distance between the ship and the enemy submarine be ‘S’. Speed of sound in water = 1450 m/s Time lag between transmission and reception of Sonar waves = 77 s In...

(d) the speed does not depend on the initial direction. Explanation:-  When the stone is thrown its total mechanical energy = K.E.+P.E.  = ½mv² + mgh ---------(i)  This energy is conserved and when near the ground...

(a) must depend on the speed of projection (b) must be larger than the speed of projection Explanation:  Since Kinetic Energy given to the stone is dependent on the speed of projection, and...

The correct answer is (c) λ`< λ EXPLANATION:     Since the reflected wave is inverted, the pulse is traveling from the lighter string to heavier string. Hence the speed of the incident...

(d) the pulses will pass through each other without any change in their shapes. EXPLANATION: The pulses travel individually without affecting each other. Simply the particle displacement is the sum of displacements...

(d) the speed does not depend on the initial direction. Explanation:-  When the stone is thrown its total mechanical energy = K.E.+P.E.  = ½mv² + mgh ---------(i)  This energy is conserved and when near...