Question

which can carry large currents ?

Answer 1

(a) \(\text{The current } (I) \text{ is calculated using Ohm's Law: } I = \frac{V}{R}.\)
 For the 2000 W heater: \(\text{Resistance } R = 25\,\Omega\), \(\text{Voltage } V = 220\,\text{V}\): \[ I_{\text{heater}} = \frac{220}{25} = 8.8\,\text{A} \]
For the 100 W bulb: \(\text{Resistance } R = 500\,\Omega\), \(\text{Voltage } V = 220\,\text{V}\): \[ I_{\text{bulb}} = \frac{220}{500} = 0.44\,\text{A} \]
Since \(8.8\,\text{A} > 0.44\,\text{A}\), the 2000 W heater can carry a larger current.
\(I_{\text{bulb}} = \frac{220}{500} = 0.44\,\text{A}\)

Answer (a): The 2000 W heater carries a much larger current (8.8 A) compared to the 100 W bulb (0.44 A).

Answer 2

Step 1: Understand the circuit rating:
- The circuit is rated at 1.0 A, meaning it can safely carry a maximum current of 1 ampere.
- Any device that draws more than 1.0 A may cause overheating or trip the fuse.

Step 2: Use the formula to calculate current:
Use Ohm’s Law to calculate the current drawn by each appliance:
\[ I = \frac{P}{V} \]
Where:
- \( I \) = current in amperes
- \( P \) = power in watts
- \( V \) = voltage, typically 230 V in households

Step 3: Calculate current drawn by a 100 W bulb:
\[ I = \frac{100}{230} \approx 0.44\,\text{A} \]
- Since 0.44 A is less than 1.0 A, the 100 W bulb can be safely used with the circuit.

Step 4: Calculate current drawn by a 2000 W heater:
\[ I = \frac{2000}{230} \approx 8.7\,\text{A} \]
- Since 8.7 A is much more than 1.0 A, the heater cannot be used with this circuit.

Step 5: Conclusion:
- The 100 W bulb can be safely used with a 1.0 A circuit.
- The 2000 W heater cannot be used with it, as it exceeds the current limit.

Answer 3

Step 1: Understand the purpose of electric boards (sockets):
Electric boards are designed to handle a specific maximum current safely. Common household boards are rated as 5 A or 15 A:
- 5 A boards are used for low-power devices (bulbs, fans, chargers).
- 15 A boards are used for high-power appliances (heaters, geysers, ovens).

Step 2: Use the formula to calculate current:
To determine how much current an appliance draws, use Ohm’s law:
\[ I = \frac{P}{V} \]
Where:
- \( I \) is the current (in amperes)
- \( P \) is the power (in watts)
- \( V \) is the voltage (typically 230 V in households)

Step 3: Calculate current for a 2000 W heater:
\[ I = \frac{2000}{230} \approx 8.7\,\text{A} \]
- This value is greater than 5 A, so it cannot be used with a 5 A board.
- It is safely within the range of a 15 A board.

Step 4: Calculate current for a 100 W bulb:
\[ I = \frac{100}{230} \approx 0.44\,\text{A} \]
- This is well within the limit of a 5 A board.

Step 5: Conclusion:
- A 2000 W heater draws more current than a 5 A board can handle, so it requires a 15 A electric board.
- A 100 W bulb draws much less current and can safely be used with a 5 A board.