In case of `a.c` circuit, Ohm's law holds good for
`{:a)` Peak values of voltage and current
`{:b)` Effective values of voltage and current
`{:c)` Instantaneous values of voltage and current

Options

A. only (a) and (b)
B. only (a)
C. only (c) is true
D. (a), (b) and (c) are true

Answer

To solve the question regarding Ohm's law in an AC circuit, we need to analyze how Ohm's law applies to different types of values: peak values, effective (RMS) values, and instantaneous values of voltage and current.

### Step-by-Step Solution:

1. **Understanding Ohm's Law**:
Ohm's law states that \( V = I \cdot R \), where \( V \) is the voltage, \( I \) is the current, and \( R \) is the resistance. This law applies to both DC and AC circuits, but we need to determine for which values it holds true in an AC circuit.

2. **Defining AC Voltage and Current**:
In an AC circuit, the voltage and current can be expressed as:
- Voltage: \( v(t) = V_0 \sin(\omega t + \phi) \)
- Current: \( i(t) = I_0 \sin(\omega t) \)
Here, \( V_0 \) and \( I_0 \) are the peak (maximum) values of voltage and current, respectively.

3. **Calculating Effective (RMS) Values**:
The effective (RMS) values for voltage and current in an AC circuit are given by:
- \( V_{\text{RMS}} = \frac{V_0}{\sqrt{2}} \)
- \( I_{\text{RMS}} = \frac{I_0}{\sqrt{2}} \)

4. **Applying Ohm's Law**:
- For peak values:
\[ V_0 = I_0 \cdot R \]
This shows that Ohm's law holds for peak values of voltage and current.
- For effective values:
\[ V_{\text{RMS}} = I_{\text{RMS}} \cdot R \]
This indicates that Ohm's law also holds for effective values of voltage and current.
- For instantaneous values:
The instantaneous values of voltage and current vary with time and do not maintain a constant relationship as defined by Ohm's law.

5. **Conclusion**:
Based on the analysis:
- Ohm's law holds for peak values (Option A) and effective values (Option B) of voltage and current.
- It does not hold for instantaneous values (Option C).

Thus, the correct answers are **Option A (Peak values of voltage and current)** and **Option B (Effective values of voltage and current)**.