Answer:
Magnitude of induced emf is 0.00635 V
Explanation:
Radius of circular loop r = 45 mm = 0.045 m
Area of circular loop 

Magnetic field is increases from 250 mT to 350 mT
Therefore change in magnetic field 
Emf induced is given by


Magnitude of induced emf is equal to 0.00635 V
Answer:
v = 12.86 km/h
v = 3.6 m/s
Explanation:
Given,
The distance, d = 13.5 km
The time, t = 21/20 h
= 1.05 h
The velocity of a body is defined as the distance traveled by the time taken.
v = d / t
= 13.5 km / 1.05 h
= 12.86 km/h
The conversion of km/h to m/s
1 km/h = 0.28 m/s
12.86 km/h = 12.86 x 0.28 m/s
= 3.6 m/s
Hence, the velocity in m/s is, v = 3.6 m/s