In which case does the bulb glow ?

Options

A.
B.
C.
D.

Explanation

To determine in which case the bulb glows, we need to analyze the conditions required for a bulb to light up in an electric circuit. Here’s a step-by-step solution:

### Step 1: Understanding the Circuit Components
A basic electric circuit consists of a power source (like a battery), connecting wires, and a load (like a bulb). For the bulb to glow, the circuit must be complete, allowing electric current to flow.

**Hint:** Identify the components of the circuit: power source, wires, and load.

### Step 2: Analyzing the Connections
1. **Case 1:** The positive terminal of the cell is connected to one terminal of the bulb, and the negative terminal of the cell is connected to the other terminal of the bulb. This forms a complete circuit, allowing current to flow through the bulb. **Result:** The bulb glows.

**Hint:** Check if both terminals of the bulb are connected to the battery.

2. **Case 2:** The positive terminal of the cell is connected to one terminal of the bulb, but the negative terminal is not connected to the other terminal of the bulb. This means the circuit is incomplete. **Result:** The bulb does not glow.

**Hint:** Ensure both terminals of the bulb have connections to the battery.

3. **Case 3:** The negative terminal of the battery is connected to the bulb, but the positive terminal is not connected to the other terminal of the bulb. This is also an incomplete circuit. **Result:** The bulb does not glow.

**Hint:** Remember that both terminals need to be connected for the circuit to be complete.

4. **Case 4:** Both terminals of the bulb are connected to the same terminal of the battery. This creates a short circuit, and there is no complete path for the current to flow through the bulb. **Result:** The bulb does not glow.

**Hint:** Check if the connections create a loop for the current to flow.

### Step 3: Conclusion
The only case where the bulb glows is Case 1, where both terminals of the bulb are properly connected to the positive and negative terminals of the battery, forming a complete circuit.

**Final Answer:** The bulb glows in Case 1.