By knowing the resistance of each bulb, we can know that which bulb will glow brighter. Higher the resistance, brighter the bulb will glow.

I case: Bulb A (60 W, 220V)

Given: Power = 60W

Voltage = 220V

To calculate the resistance by the formula V = IR, first, we need to find out the current flowing in the bulb. Apply the formula:

P = VI

•

• I = 0.27A

Now apply the formula:

V = IR

•

• R = 814.8 ohm

Thus, the resistance of the bulb A is 814.8 ohm.

II case: Bulb B (100 W, 220V)

Given: Power = 100W

Voltage = 220V

To calculate the resistance by the formula V = IR, first, we need to find out the current flowing in the bulb. Apply the formula:

P = VI

•

• I = 0.45A

Now apply the formula:

V = IR

•

• R = 488.8 ohm

Thus, the resistance of the bulb B is 488.8 ohm.

The resistance of the bulb A is higher. Hence it will glow more brighter than bulb B.

OR

It is given that in a voltmeter there are 20 divisions between the 0 mark and 0.5 V mark.

Given: Number of divisions = 20

Distance between the two marks = 0.5V – 0V = 0.5V

We need to find out the least count of a voltmeter.

Least count: The smallest measured value of any instrument is said to be the least count of that instrument. It is measured as:

• Least count of voltmeter = 0.025V

Thus, the least count of the given voltmeter is 0.025V.