Calculating Relay Resistance for 12V Circuit

[Punch]

Homework Statement

A relay switches on when the current through the coil reaches 0.0048A.

In a circuit, a battery of 12V is connected in series with this relay it switches on when another resistor of 800 Ohm is connected to it.

Calculate the resistance of the relay.

Homework Equations

The Attempt at a Solution

V= IR
12V = 0.0048A * (800 ohm + coil resistance)

12V / 0.0048A = 800 ohm + coil resistance

coil resistance = 2500 ohm - 800 ohm
=1700 ohm

However, I am not sure if I am on the right track...

 

[ideasrule]

Is the circuit with the battery and the resistor supposed to deliver 0.0048A? If so, your solution is right.

 

[Punch]

Is the circuit with the battery and the resistor supposed to deliver 0.0048A? If so, your solution is right.

from the first line, "A relay switches on when the current through the coil reaches 0.0048A."

so can i conclude that the current passing through the coil has reached 0.0048A? which means that current in the circuit is 0.0048A

however, this question is worth 4 marks and it seems to easy for a usual 4 mark question...