Question

A circuit with a resistance of `6 Omega` has a fuse that melts at `8 A`. Can a voltage of `21 V` be applied to the circuit without blowing the fuse?

Answer 1

It works without melting.

Explanation:

To solve it, we apply the resistance formula:
`"Resistance" = "Voltage"/"Current"`
If `"Current >= 8`, the circuit wont work.

So, we check the limit of the voltage, when Current is 8, and if the voltage is higher than 21, the circuit will work:
`6 = "Voltage"_("limit")/8 => "Voltage" = 6 * 8 = 48 V`

So, 21 < 48. It works without melting.