Advertisements
Advertisements
Question
Show by a diagram how two resistors R1 and R2 are joined in parallel. Obtain an expression for the total resistance of the combination.
Advertisements
Solution
On applying Ohm's law to the two resistors separately, we further
Have
`"I"_1 = "V" / "R"_1`
`"I"_2 = "V" / "R"_2`
`"I" = "I"_1 + "I"_2 `
`"V"/"R" = "V"/"R"_1+ "V"/"R"_2`
`1/"R"=1/"R"_1+1/"R"_2`
APPEARS IN
RELATED QUESTIONS
If the potential difference across the ends of a conductor is 220 V and the resistance of the conductor is 44 Ω (ohm), then the current flowing through is _________.
- 0.2 A
- 0.5 A
- 2 A
- 5 A
When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Calculate the value of the resistance of the resistor.
Name the law which is illustrated by the above V−I graph.
What is an ohmic resistor? Give one example of an ohmic resistor. Draw a graph to show its current voltage relationship. How is the resistance of the resistor determined from this graph?
In the circuit shown below in Fig, calculate the value of x if the equivalent resistance between A and B is 4 Ω.
A wire has a length of 2.0 m and a resistance of 5.0 Ω. Find the electric field existing inside the wire if it carries a current of 10 A.
Calculate the effective resistance across AB?
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.
What is the resistance of a conductor through which a current of 0.5 A flows when a potential difference of 2V is applied across its ends?
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.
