JEE MAIN - Physics (2021 - 22th July Evening Shift - No. 25)
In an electric circuit, a cell of certain emf provides a potential difference of 1.25 V across a load resistance of 5$$\Omega$$. However, it provides a potential difference of 1 V across a load resistance of 2$$\Omega$$. The emf of the cell is given by $${x \over {10}}V$$. Then the value of x is ______________.
Answer
15
Explanation
_22th_July_Evening_Shift_en_25_2.png)
In case (a) $$\varepsilon = {{1.25} \over 5}(5 + r)$$
$$ \Rightarrow 4\varepsilon = 5 + r$$ ..... (1)
In case (b), $$\varepsilon = {1 \over 2}(2 + r)$$
$$ \Rightarrow 2\varepsilon = 2 + r$$ ..... (2)
From equation (1) & (2)
$$2\varepsilon = 3 \Rightarrow \varepsilon = 1.5$$
or x = 15
Comments (0)
