Step 1: Understand the transaction.
A Ltd. has purchased a plant worth Rs. 4,00,000 from B Ltd., and the payment is made by issuing fully paid shares of Rs. 100 each at par.
Step 2: Pass the journal entry.
When shares are issued at par, the journal entry is as follows:
\[
\text{Journal Entry:}
\]
\[
\text{Plant Account} \, \text{Dr. \, 4,00,000 \quad \text{(Value of the plant purchased)}
\]
\[
\text{Share Capital Account} \, \text{Cr. \, 4,00,000 \quad \text{(Fully paid shares issued at par)}
\]