A resistance R is connected at the n terminal of a p-n junction in series. An AC voltage is applied across this circuit. Which of the following are true for the circuit?

Options

A. Voltage across diode will be positive half cycles.
B. Voltage across diode will be positive half cycle
C. Voltage across resistance will be negative half cycles.
D. Voltage across resistance will be positive half cycles

Explanation

To solve the problem, let's analyze the behavior of the p-n junction diode when an AC voltage is applied across it with a resistance connected in series at the n terminal.

### Step-by-Step Solution:

1. **Understanding the p-n Junction**:
- A p-n junction consists of a p-type semiconductor (which has an abundance of holes) and an n-type semiconductor (which has an abundance of electrons). When a voltage is applied, the behavior of the junction depends on the polarity of the voltage.

2. **Applying AC Voltage**:
- An AC voltage alternates between positive and negative cycles. During the positive half cycle, the p-type side is connected to the positive terminal of the voltage source, and the n-type side is connected to the negative terminal. This configuration allows current to flow through the diode (forward bias).
- During the negative half cycle, the p-type side is connected to the negative terminal, and the n-type side is connected to the positive terminal, which reverse biases the diode. In this case, the diode does not conduct current.

3. **Current Flow**:
- In the forward bias (positive half cycle), the diode conducts, and current flows through the resistance R.
- In the reverse bias (negative half cycle), the diode does not conduct, and hence no current flows through the resistance R.

4. **Voltage Across the Diode**:
- During the positive half cycle, the voltage across the diode is positive as it is forward biased.
- During the negative half cycle, the voltage across the diode is negative as it is reverse biased.

5. **Voltage Across the Resistance**:
- The voltage across the resistance R will be positive during the positive half cycle (when the diode conducts) and will be zero during the negative half cycle (when the diode does not conduct).

### Conclusion:
Based on this analysis, we can evaluate the options provided in the question:

1. **Voltage across the diode will be positive half cycles**: This is **true** during the positive half cycle and **false** during the negative half cycle.
2. **Voltage across resistance will be negative half cycles**: This is **false** because the voltage across the resistance is zero during the negative half cycle.
3. **Voltage across resistance will be positive half cycles**: This is **true** during the positive half cycle.

### Final Answer:
- The correct options are:
- Voltage across the diode will be positive during the positive half cycle.
- Voltage across resistance will be positive during the positive half cycle.