A closely wound rectangular coil of 80 turns has dimensions of 25.0 cm by 40.0 cm. The plane of the coil is rotated from a position where it makes an angle of 43.0 ∘ with a magnetic field of 1.40 T to a position perpendicular to the field. The rotation takes 0.0700 s . What is the average emf induced in the coil?

The average induced emf is 50.88 V

Explanation:

Given;

number of turns, N = 80 turns

angle between the plane of the coil and magnetic field, θ =  43°

strength of magnetic field, B = 1.40 T

time to make 80 turns = 0.0700 s

where;

A is the area of the coil = 0.25 x 0.4 = 0.1 m²

If the plane makes an angle of  43° with a magnetic field to a position perpendicular to the field, then the initial angle θi = 90 - 43 = 47° and the final angle θf  with the field = 0

Therefore, the average induced emf is 50.88 V

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.