When a 100-ω resistor is connected across the terminals of a battery of emf ε and internal resistance r, the battery delivers 0.794 w of power to the 100-ω resistor. when the 100-ω resistor is replaced by a 200-ω resistor, the battery delivers 0.401 w of power to the 200-ω resistor. what are the emf and internal resistance of the battery?

The emf and internal resistance of the battery are 9 volt and 2.04 Ω

Explanation:

Given that,

First resistor

Power

Second resistor

Power

We need to calculate the emf and internal resistance

Using formula of emf

For first resistor

....(I)

For second resistor

.....(II)

From equation (I) and (II)

Using component of dividend rule

Now, Put the value of internal resistance in equation (I)

Hence, The emf and internal resistance of the battery are 9 volt and 2.04 Ω

the answer is b i think

wire in brush may conduct electricity from cell to drill and vice versa electrc shock possible