Q23 of 31 Page 252

Measure the resistance of a bulb (filament) in open circuit with a multi-meter. Make a circuit with elements such as a bulb, a battery of 12V and key in series. Close the key. Then again measure the resistance of the same bulb (filament) every 30 seconds. Record the observations in a proper table. What can you conclude from the above results?

We can measure current in ammeter and voltage using voltmeter every 30 seconds. We will found the resistance by applying formula R = V/I i.e. Ohm’s law for every readings of ammeter and voltmeter. We will see resistance is constant. Since resistance is constant so it represents Ohm’s law. If we plot a graph taking voltage in Y axis and current in X axis, a straight line will be obtained indicating that resistance is constant and it obeys Ohm’s law.


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State Ohm's law. Suggest an experiment to verify it and explain the procedure.

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Draw a circuit diagram for a circuit in which two resistors A and B are connected in series with a battery and a voltmeter is connected to measure the potential difference across the resistor A.

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