When a steady direct current flows through a coil, the only opposition to the flow of current is the resistance of the wire from which the coil is made.

True

Explanation:

This is true statement because in DC circuit there is only resistance which comes into play of opposition of current.

In DC circuit there is no role of frequency in if there is no frequency then there will no inductive reactance and no capacitive reactance to oppose the current flow

So in DC circuit only resistance is responsible to oppose the flow of current

So this is a true statement

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