What kind of electric cell is considered to be rechargeable?
A. Storage cell
Answer:
To your left
Explanation:
The direction of the force exerted on charged particle due to a magnetic field is given by the right-hand-rule, where:
- The index finger indicates the direction of motion of the electron
- the middle finger gives the direction of the magnetic field
- the thumb gives the direction of the force if the particle is positively charged - otherwise, the direction is reversed
in this case, we have an electron (so, a negatively charged particle):
- The direction of motion (index finger) is horizontal, toward you
- The electron begins to curve upward as it enters the field, so this means that the force exerted on the electrons is upward --> the thumb must point downward (because the electron is negatively charged)
- The index finger gives us the direction of the magnetic field: therefore, to your left.
Answer:
(a) The self inductance, L = 21.95 mH
(b) The energy stored, E = 4.84 J
(c) the time, t = 0.154 s
Explanation:
(a) Self inductance is calculated as;

where;
N is the number of turns = 1000 loops
μ is the permeability of free space = 4π x 10⁻⁷ H/m
l is the length of the inductor, = 45 cm = 0.45 m
A is the area of the inductor (given diameter = 10 cm = 0.1 m)

(b) The energy stored in the inductor when 21 A current ;

(c) time it can be turned off if the induced emf cannot exceed 3.0 V;

The answer is C..........