If an alternating voltage is applied across a diode in series with a load, then

Options

A. a DC voltage appears across load
B. an AC voltage appears across load
C. a pulsating voltage appears across load
D. no voltage appears across load

Explanation

To solve the question, we need to analyze the behavior of a diode when an alternating voltage (AC) is applied across it in series with a load. Here’s a step-by-step solution:

### Step 1: Understanding the Circuit
When an alternating voltage is applied to a circuit that includes a diode and a load resistor in series, the diode will respond differently to the positive and negative halves of the AC waveform.

**Hint:** Consider how a diode behaves in forward and reverse bias.

### Step 2: Forward Bias Condition
During the positive half-cycle of the AC voltage, the diode becomes forward-biased. In this state, it allows current to flow through the circuit. The current will flow through the load resistor, and a voltage drop will occur across the load.

**Hint:** Remember that in forward bias, a diode acts like a closed switch.

### Step 3: Reverse Bias Condition
During the negative half-cycle of the AC voltage, the diode becomes reverse-biased. In this condition, the diode blocks current flow, effectively acting like an open switch. As a result, no current flows through the load resistor, and the voltage across the load drops to zero.

**Hint:** Think about how the diode prevents current flow in reverse bias.

### Step 4: Current and Voltage Characteristics
The current flowing through the load will be pulsating. It will be present during the positive half-cycles and will be zero during the negative half-cycles. Consequently, the voltage across the load will also be pulsating, reflecting the current flow.

**Hint:** Visualize the waveform of the current and voltage across the load.

### Step 5: Conclusion on Voltage Across Load
Since the diode only allows current to flow during the positive half-cycles of the AC input, the output voltage across the load will not be a constant DC voltage but rather a pulsating DC voltage. This means that the load experiences a series of voltage pulses corresponding to the positive cycles of the AC input.

**Hint:** Consider how the shape of the voltage waveform relates to the current waveform.

### Final Answer
When an alternating voltage is applied across a diode in series with a load, a pulsating DC voltage appears across the load. The voltage is zero during the negative half-cycles of the AC input and pulsates during the positive half-cycles.