1.
[1]What is the lowest
resistance that can be obtained
by combining four coils of
resistors of 4, 8
, 12 and
24 Ohm ?
2.
[2]Will
current flow more easily through a thick wire or a thin
wire of the same material, when connected to the same source
? Why ? Name the factors
on which the resistance of a
wire depends.
3.
[2]Write the general principle involved in generating
nuclear energy. Name
one fuel used in a nuclear reactor.
4.
[2]What is a solenoid ? Draw a
sketch to show the pattern of field lines due to a solenoid carrying current.
5.
[2]An
electric lamp is marked 220V, 100W. It is used
for 5 hours daily. Calculate
(a)
Its resistance while
glowing
(b)
Energy consumed in
kWh/day.
6.
[3]Giving a schematic diagram of bio-gas plant
explain the production of bio-gas and manure. Give the composition of bio-gas.
7.
[3]
(a) For the circuit shown above
in the diagram, calculate :
(i) Value
of current through the 30 ohm resistor.
(ii) Total resistance of the circuit.
(b) Give two
advantages of connecting electrical
devices in parallel with battery.
8.
[3]
(a) Describe an activity
to draw a magnetic field line outside a bar magnet from one pole
to another.
(b) List any two properties of magnetic field lines.
9.
[3]
(a) Electric fuse is an important
component of all domestic circuits. Why
?
(b) An
electric oven of rating 2 kW, 220V is operated in a
domestic circuit with a current
rating of 5A. What
10.
[5]
(a) State ohm’s law.
Express it mathematically.
(b) Write
symbols used in electric
circuits to represent :
(i) Variable
resistance
(ii) Voltmeter.
(c) An
electric bulb is rated 220V and 100W.
When it is operated on 110V,
what will be the power consumed ?
‘OR’
[5] (a) Why
is the series arrangement not
used for domestic circuits ?
(b) Why is the tungsten used almost
exclusively for filament of electric lamps ?
(c) Why
are the conductors of electric heating devices such
as bread toasters and electric
irons made of an alloy rather than
a pure metal ?
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