Afixed 15.3-cm-diameter wire coil is perpendicular to a magnetic field 0.77 t pointing up. in 0.20 s , the field is changed to 0.26 t pointing down. what is the average induced emf in the coil?

Induced emf will be 0.468 volt

Explanation:

We have given diameter of wire d = 15.3 cm

So radius

So area

Change in magnetic field dB = 0.26 - 0.77 = -0.51 T

Time for change in magnetic field dt = 0.26 sec

We know that emf is given by

when a device is used in a circuit in which the voltage is 81 v, the current flowing through the device is 3 a. what is the resistance of the device?

a. 27 ω

b. 40.5 a

c. 243 ω

d. 243 a

the correct answer is a. 27