Explanation :
It is given that,
Diameter of the coil, d = 20 cm = 0.2 m
Radius of the coil, r = 0.1 m
Number of turns, N = 3000
Induced EMF, 
Magnitude of Earth's field, 
We need to find the angular frequency with which it is rotated. The induced emf due to rotation is given by :




So, the angular frequency with which the loop is rotated is 159.15 rad/s. Hence, this is the required solution.
Answer:
(a) The force between them quadruples
Explanation:
According to coulomb's law, initial force between the two charged objects is given as;

where;
k is coulomb's constant
q₁ is the charge on the first object
q₂ is the charge on the second object
r is the distance between the two objects
When the charges on both objects are doubled, then;
q₁ = 2q₁
q₂ = 2q₂
Force between the two charged objects will become

Therefore, the force between them quadruples
Answer: feet first
Explanation:
It is always the safest to enter with your feet first. You can become paralyzed or injure you neck if you dive into a body of water that is too shallow. Therefore its always best to dive feet first instead.
Answer:
Uncertainty in position of the bullet is 
Explanation:
It is given that,
Mass of the bullet, m = 35 g = 0.035 kg
Velocity of bullet, v = 709 m/s
The uncertainty in momentum is 0.20%. The momentum of the bullet is given by :


Uncertainty in momentum is,


We need to find the uncertainty in position. It can be calculated using Heisenberg uncertainty principal as :




Hence, this is the required solution.