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प्रश्न
Conceptual question.
A bird sitting on a high power electric line is still safe. How?
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उत्तर
Birds don’t get shocked when they sit on electrical wires because they are not good conductors of electricity. Electricity flowing through a single power line at 35,000 volts will continue along the path of least resistance and bypass birds, because there is no difference in electrical potential.
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संबंधित प्रश्न
The values of current (I) flowing through a given resistor of resistance (R), for the corresponding values of potential difference (V) across the resistor are as given below:
| V (volts) | 0.5 | 1.0 | 1.5 | 2.0 | 2.5 | 3.0 | 4.0 | 5.0 |
| I (amperes) | 0.1 | 0.2 | 0.3 | 0.4 | 0.5 | 0.6 | 0.8 | 1.0 |
Plot a graph between current (I) and potential difference (V) and determine the resistance (R) of the resistor.
Which device is used to measure p.d?
The p.d. across a lamp is 12 V. How many joules of electrical energy are changed into heat and light when:
a charge of 5 C passes through it?
Define the following:
Potential difference
A cell of e.m.f 2.0 V and internal resistance 1Ω is connected to the resistors of 3Ω and 6Ω in series. Calculate:
(i) the current drawn from the cell,
(ii) the p.d. across each resistor,
(iii) the terminal voltage of the cell and
(iv) the voltage drop.
A 10 m long wire of a particular material is of resistance 5Ω What will be the resistance of 10m long wire of the same material but the double radius.
Exercise.
Calculate the amount of charge that would flow in 2 hours through an element of an electric bulb drawing a current of 2.5 A.
Two charged spherical conductors of radius R1 and R2 are connected by a wire. Then the ratio of surface charge densities of the spheres `(σ_1//σ_2 )` is ______.
Twenty-seven drops of the same size are charged at 220 V each. They combine to form a bigger drop. Calculate the potential of the bigger drop.
Two charged spherical conductors of radius R1 and R2 are connected by a wire. Then the ratio of surface charge densities of the spheres (σ1/σ2 ) is ______
