The correct answer is: C. The power dissipation in each bulb is not same.
Explanation:
When four bulbs of 40 W each are connected in series, the current through each bulb is the same. This is because the current is the same in a series circuit. However, the voltage across each bulb is not the same. This is because the voltage across a resistor is proportional to the current through it, and the current through each bulb is the same, but the resistance of each bulb is different. The power dissipation in each bulb is equal to the voltage across the bulb times the current through the bulb. Since the voltage across each bulb is different, the power dissipation in each bulb is also different.
The following is a more detailed explanation of each option:
- Option A: The current through each bulb in same.
This is true because the current is the same in a series circuit. The current is equal to the total voltage divided by the total resistance. In this case, the total voltage is the voltage of the battery, and the total resistance is the sum of the resistances of the four bulbs. Since the resistances of the four bulbs are the same, the total resistance is also the same. Therefore, the current through each bulb is the same.
- Option B: The voltage across each bulb is not same.
This is true because the voltage across a resistor is proportional to the current through it, and the current through each bulb is the same, but the resistance of each bulb is different. The resistance of a bulb is determined by its filament material and length. The filament material and length of each bulb are different, so the resistance of each bulb is also different. Therefore, the voltage across each bulb is not the same.
- Option C: The power dissipation in each bulb is not same.
This is true because the power dissipation in a resistor is equal to the voltage across the resistor times the current through the resistor. Since the voltage across each bulb is different, the power dissipation in each bulb is also different.
- Option D: None of the above.
This is not true because Option C is true.