Read the passage and answer the question.

When the two types of semiconductors are joined together, diffusion of electrons and holes from their side of excess takes place and continues for a while after which a depletion layer is formed close to the junction on either side which stops any further diffusion of these carriers. A potential difference appears to have set up at the junction.

Assertion (A) : A large electric field is set-up across the junction.

Reason (R) : Potential difference is developed across the junction. Which of the following is best suited?

(A) is correctly explained by (R)

The potential difference is small but across a very minute stretch of length, hence the electric field is developed and the field so developed is of the order of \( { 10}^{ 5} \)