The emf induced = B*l*v where B is the flux density, l the length of the conductor and v the velocity of the conductor. In the given case B = 0.035 N/amp.meter, l = 0.86 and v = 6 m/sec
emf = 0.035*0.86*6 = 0.1806 v ≈ 0.18 v
choice: D
The answer that best suits this should be D
Answer:
The string will break with a speed of 20 m/s.
Explanation:
It is given that,
Tension at which the string just breaks, T = 400 N
Mass of the stone, m = 10 kg
Radius of the circle, r = 10 m
We need to find the speed at which the string will break. The boy continuously increases the speed of the stone. The tension acting on the stone is equal to the centripetal force. It is a force that acts towards the center of circle. It is given by :



v = 20 m/s
So, the string will break with a speed of 20 m/s. Hence, this is the required solution.
10% is about how much travels down from level to level