Assertlon (A). When an electric motor is started the Initial current In It Is considerably more than the final current
Reasoning : The current falls due to the fall In the back emf

Options

A. a. Assertion is true, Reason is false
B. b.Assertion is false, Reason is true
C. c.Both Assertion and Reason are true and Reason is the correct explanation of Assertion·
D. d.Both Assertion and Reason are true but Reason is not the correct explanation of Assertion

Answer

To solve the question, we need to analyze the assertion and reasoning provided regarding the behavior of an electric motor when it is started.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states: "When an electric motor is started, the initial current in it is considerably more than the final current."
- This is true. When an electric motor starts, it draws a large amount of current because the back electromotive force (back EMF) is initially zero. As the motor accelerates, the back EMF increases, which reduces the current.

2. **Understanding the Reasoning**:
- The reasoning states: "The current falls due to the fall in the back EMF."
- This statement is incorrect. The current actually falls due to the rise in back EMF as the motor speeds up. Initially, when the motor starts, the back EMF is zero, allowing maximum current to flow. As the motor accelerates, the back EMF increases, which opposes the supply voltage and reduces the current.

3. **Analyzing the Motor Circuit**:
- The voltage equation for the motor can be expressed as:
\[ V_s = I_a R_a + E_b \]
- Where \(V_s\) is the supply voltage, \(I_a\) is the armature current, \(R_a\) is the armature resistance, and \(E_b\) is the back EMF.
- At startup, \(E_b = 0\), so:
\[ I_a = \frac{V_s}{R_a} \]
- As the motor speeds up, \(E_b\) increases, leading to:
\[ I_a = \frac{V_s - E_b}{R_a} \]
- This shows that as \(E_b\) increases, \(I_a\) decreases.

4. **Conclusion**:
- The assertion is true: the initial current is greater than the final current.
- The reasoning is false: the current falls due to the rise in back EMF, not a fall in back EMF.

### Final Answer:
- Assertion (A) is true.
- Reasoning (R) is false.
- Therefore, the correct option is that the assertion is true and the reason is false.