Advertisements
Advertisements
Question
In the circuit shown in fig. 6, find the reading of the ammeter A when the switch S is
(a) Opened.
(b) Closed.
Advertisements
Solution
(a) When the switch S is opened, resistance 60Ω is not connected in the circuit and current flows through the 20Ω resistor.
:. Resistance of the circuit. when the switch is open:
R= 20 + 5 = 25 Ω
Given, voltage = 10 V
:. current through the circuit, I= `"V"/"R" = 10/25` = 0.4 A
The reading of the ammeter is thus 0 .4 A, when the switch is open.
(b) When the switch is closed, resistance 60 Ω gets connected to the circuit.
Thus, in the circuit the parallel combination of 60 Ω and 200 resistors is connected in series with the 5 Ω resistor.
:. Resistance in parallel, `1/"R"_"P" = 1/60 + 1/20 = (1 + 3)/60 = 4/60` Ω
or `"R"_"P" = 15 Ω
Now, total resistance of the circuit= 15 + 5 = 20 Ω
current through the circuit, I= `"V"/"R" = 10/20 = 0.5 "A"`
The reading of the ammeter is thus 0 .5 A, when the switch is closed.
APPEARS IN
RELATED QUESTIONS
How many microamperes are there in 1 ampere?
Fill in the folloing blank with suitable words:
Current is measured in ............... using an ............... placed in ............... in a circuit.
Ten bulbs are connected in a series circuit to a power supply line. Ten identical bulbs are connected in a parallel circuit to an identical power supply line.
(c) In which circuit, if one bulb blows out, all other will stop glowing?
A given wire of resistance 1 Ω is stretched to double its length. What will be its new resistance?
Tell the odd one out. Give a proper explanation.
An electric current flowing in a wire creates ______ around the wire.
Tick(✓) the correct choice in the following:
The outer casing of an electric iron is generally connected to earth in order
to
A charge of 80 C flows in a conductor for 2 minutes.
(a) Calculate the current flowing through the conductor.
(b) If the current through a heater is 4 A what charge must be passing in 8 seconds?
One unit of electrical energy consumed is equal to 1000 kilowatt-hour.
