Advertisements
Advertisements
प्रश्न
The potential difference between the terminals of a battery of emf 6.0 V and internal resistance 1 Ω drops to 5.8 V when connected across an external resistor. Find the resistance of the external resistor.
उत्तर
Given:-
Emf of the battery, E = 6 V
Internal resistance, r = 1 Ω
Potential difference, V = 5.8 V
Let R be the resistance of the external resistor.
Applying KVL in the above circuit, we get:-
\[E - i(R + r) = 0\]
\[ \Rightarrow i = \frac{E}{R + r}\]
\[ = \frac{6}{R + 1}\]
Also,
\[V = E - ir\]
\[ \Rightarrow 5 . 8 = 6 - \frac{6}{R + 1} \times 1\]
\[\frac{6}{R + 1} = 0 . 2\]
\[R + 1 = \frac{6}{0 . 2} = 30\]
\[R = 29 \Omega\]
APPEARS IN
संबंधित प्रश्न
In the following potentiometer circuit, AB is a uniform wire of length 1 m and resistance 10 Ω. Calculate the potential gradient along the wire and balance length AO (= l).
When 5 V potential difference is applied across a wire of length 0.1 m, the drift speed of electrons is 2.5 x 10-4 m/s. If the electron density in the wire is 8 x 1028 m-3, calculate the resistivity of the material of the wire.
Describe the working principle of a solar cell. Mention three basic processes involved in the generation of emf.
Why are Si and GaAs preferred materials for solar cells?
Why is potentiometer preferred over a voltmeter for comparison of emf. of cells?
The emf of a cell is always greater than its terminal voltage. Why? Give reason.
Identify the correct options.
(a) An ammeter should have small resistance.
(b) An ammeter should have large resistance.
(c) A voltmeter should have small resistance.
(d) A voltmeter should have large resistance.
Find the potential difference Va – Vb in the circuits shown in the figure.
A voltmeter of resistance 400 Ω is used to measure the potential difference across the 100 Ω resistor in the circuit shown in the figure. (a) What will be the reading of the voltmeter? (b) What was the potential difference across 100 Ω before the voltmeter was connected?
If a constant potential difference is applied across a bulb, the current slightly decreases as time passes and then becomes constant. Explain.
The potential difference across the terminals of a battery of emf 12 V and internal resistance 2 Ω drops to 10 V when it is connected to a silver voltameter. Find the silver deposited at the cathode in half an hour. Atomic weight of silver is 107.9 g mol−1.
A potential difference of 220 V is maintained across 12000 Ω rheostat. Then voltmeter V has a resistance of 6000 Ω and point C is at one fourth the distance from a to b. Then the reading of voltmeter is ______.
In the circuit in figure the potential difference across P and Q will be nearest to
The terminal potential difference of a cell is greater than its e.m.f when it is ______
