Acoil of area 0.2 m2 and total resistance 100 ω is rotated at a rate of 60 rev/s. its axis of rotation is perpendicular to a 0.5 t magnetic field. how many turns are in the coil if energy is delivered to it at a maximum rate of 1420 w?

The concept necessary to solve this problem is the mathematical definition of the electromotive force or induced voltage. Theoretically the electromotive force is the electrical action produced by a non-electrical source. Mathematically it can be expressed as

Where

N = Number of loops

B = Magnetic Field

A = Cross-sectional Area

Angular velocity

Re-arrange to find N,

In parallel, we can also consider the rate of energy change expressed in terms of the induced voltage, that is,

Where

R = Resistance

The previous equation can be expressed as

Equating the two expression we have

Replacing with our values we have that

Therefore the number of turns are 10.

the answer would be a

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards