Aconducting bar rests on two parallel horizontal rails 50 cm apart forming a square area. the resistance of the bar and the rails is assumed to be constant and equal to 0.05 ω. a uniform magnetic field 0.5 t is perpendicular to the plane of the rails. the value of the field is uniformly reduced to zero in a time of 0.1 s. what is the maximum value of the force acting on the bar during that time?

Force = 6.25 N

Explanation:

Given:

Distance between the rails, l = 50cm = 0.5m

since it is forming a square area. thus, area = 0.5² m²

Resistance of the bar = 0.05Ω

Magnetic field, B = 0.5T

Time = 0.1s

Now,

The value for EMF is given as

EMF = (ΔArea x Field) /time

substituting the values in the above equation we get

EMF = (0.5² x 0.5) /0.1 = 1.25 Volts

now,

Current, i = EMF/ Resistance

substituting the values in the above equation we get

i = 1.25/0.05 = 25 A

Now the force is given as:

Force = i x l x B

Force = 25 x 0.5 x 0.5

Force = 6.25 N

find the surface area of the sphere to the nearest square unit. use a calculator.

a. 254 in.2

b. 64 in.2

c. 127 in.2

d. 1,018 in.2