Advertisements
Advertisements
Question
A battery of e.m.f. 15 V and internal resistance 3 ohm is connected to two resistors of resistance 3 ohm and 6 ohm in series. Find:
(i) The current through the battery,
(ii) The p.d. between the terminals of the battery.
Advertisements
Solution
Given, emf, e = 15 v
Internal resistance, r = 3 `Omega`
Resistance of given two resistors in series, R, = 3 + 6 = 9 `Omega`
(i) Current = `"emf"/"Total resistance of circuit" = 15/(9 + 3) = 15/12` = 1.25 A
(ii) Potential difference= emf - voltage drop= e - (Ir)
Now, voltage drop= current x internal resistance= 1.25 x 3 = 3.75
.·. p.d. = 15 - 3.75= 11.25V
APPEARS IN
RELATED QUESTIONS
1 A = _________ mA
- 102
- 103
- 10-3
- 10-6
<p> Define the unit of electric current (or Define ampere).
The p.d. across a 3 Ω resistor is 6 V. The current flowing in the resistor will be:
(a) `1/2A`
(b) 1 A
(c) 2 A
(d) 6 A
Tick(✓) the correct choice in the following:
A three pin plug is connected to the lead for a 1 kW electric iron to be
used on a 250 V supply. Which of the following statements is not correct?
60 joules of heat was dissipated in a resistor when 20 C flowed for 5 s. Calculate:
(a) P.d. across the resistor,
(b) Resistance of the resistor, and
(c) Average power dissipated in the resistor.
Electrical appliances have voltage and power ratings as listed below. Which
has the larger working resistance?
| Appliances | Voltage (V) | Power (W) |
| (a) Washing machine | 250 | 3000 |
| ( b) Television | 240 | 160 |
| (c)240 | 240 | 1500 |
| ( d) Hair curler | 250 | 20 |
| ( e) Car head lamp | 12 | 36 |
A bulb is connected to a battery of p.d. 4 V and internal resistance 2.5 Ω . A steady current of 0.5 A flows through the circuit. Calculate:
The energy dissipated in the bulb in 10 minutes.
Three resistances, of which two are equal when connected in series have an effective resistance of 30 ohms. When the three resistances are connected in parallel, the effective resistances is 3 ohms. Find the values of the individual resistances.
State whether true or false. If false, correct the statement.
Current can produce magnetic field.
