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प्रश्न
Vinita and Ahmed demonstrated a circuit that operates the two headlights and the two sidelights of a car, in their school exhibition. Based on their demonstrated circuit, answer the following questions.
- State what happens when switch A is connected to:
a) Position 2
b) Position 3 - Find the potential difference across each lamp when lit.
- Calculate the current.
a) in each 12 Ω lamp when lit.
b) In each 4 Ω lamp when lit.
OR - Show, with calculations, which type of lamp, 4.0 Ω or 12 Ω, has the higher power.
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उत्तर
- (a) 12 Ω lamps (only) on.
(b) 4 Ω lamps (only) on. - 12 V for both sets of lamps and all of them are in parallel.
- a) 12 Ω lamps are on when the wire is connected to position 2.
The voltage across both 12 Ω lamps = 12 V.
V = IR (Ohm’s law)
`"I" = "V"/"R" = 12/12 = 1 "A"`
b) 4 Ω lamps are on when the wire is connected to position 3.
The voltage across both 4 Ω lamps = 12 V.
V = IR (Ohm’s law)
`"I" = "V"/"R" = 12/4 = 3 "A"`
OR - `"P" = "V"^2/"R"`
All lamps are in parallel and hence the same V for all lamps.
For 4 Ω lamps → P = `(12 xx 12)/4` = 36 W
For 12 Ω lamps → P = `(12 xx 12)/12` = 12 W
Hence 4 Ω lamps will have higher power.
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संबंधित प्रश्न
In an experiment of verification of Ohm’s law following observations are obtained.
|
Potential difference V (in volt) |
0.5 | 1.0 | 1.5 | 2.0 | 2.5 |
| current I (in ampere) | 0.2 | 0.4 | 0.6 | 0.8 | 1.0 |
Draw a V-I graph and use this graph to find:
- the potential difference V when the current I is 0.5 A,
- the current I when the potential difference V is 0.75 V,
- the resistance in a circuit.
An ammeter placed in series with an electric radiator reads 0.5 amps and a voltmeter placed across it reads 230 volts. What is the resistance of the radiator?
Choose the correct alternative.
Which of the following is an ohmic conductor?
Answer the following question.
Distinguish between Ohmic and non-ohmic substances; explain with the help of example.
SI unit of resistance is:
The ratio of the potential difference to the current is known as ________.
State Ohm’s law.
Explain the equivalent resistance of a parallel resistor network.
Two cells of same emf E but internal resistance r1 and r2 are connected in series to an external resistor R (Figure). What should be the value of R so that the potential difference across the terminals of the first cell becomes zero.
