SUMMER HOLIDAY HOMEWORK
Session 2013-14
Name: _____________________
S.No.:1
Date: _______/ _05_____/ 2013___
D-II, Vasant Kunj, New Delhi - 110070
Subject: Physics
Class: X
Topic: Electricity
GENERAL INSTRUCTIONS:
A: All questions are compulsory.
B: Parts of same questions to be attempted together.
C: Draw well labelled neat diagrams where required. Use a sharp pencil.
D:Do the questions in physics notebook.
1.
Two wires of same material are having length L and 2L. Compare their resistance and
resistivity.
2.
Why are coils of electric toaster and electric iron made of an alloy rather than a pure
metal?
3.
Two wires are of same length and radius but one of them is copper and the other is of
iron. Which will have more resistance? (Given the resistivity of copper = 1.62 x 10 -8
ohm meter and resistivity of iron = 10 x 10-8 ohm meter.
4.
Define 1KWh. Give the relation between 1kwh and Joule.
5.
State which has a higher resistance. A 50W or 25W lamp. Also find the ratio of their
resistances.
6.
A wire of resistance 5 Ohm is spent in the form of closed circle. What is the resistance
between 2 points at the ends of any diameter of the circle?
7.
Calculate the amount of charge that would flow in one hour through the element of an
electric iron drawing a current of 0.4 amps.
8.
A electric toaster of resistance 20 Ohm takes a current of 5A. Calculate the heat
developed in 30 s.
9.
A bulb is rated at 5V, 100mA. Calculate its (1) Power (2) Resistance
10.
Name two special characteristics of a heater coil.
Short answer questions (3 marks)
1.
Define resistance and resistivity. Give the relation between them. Explain the dependence
of resistance on temperature.
2.
With the help of neat circuit, derive the expression for the equivalent resistance of 3
resistances connected in series.
3.
With the help of neat circuit, derive the expression for the equivalent resistance of 3
resistances connected in parallel
4.
(a ) Draw the circuit consisting of a battery of five 2V cells, 5ohm resistor, 10 ohm
resistor, 15 ohm resistor and a plug key. All connected in series (b) calculate the current
THS,VK, CL.X Physics Topic: Electricity Summer HHW Session:2013-14
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passing through the above circuit when key is closed.
5.
Two identical resistors each of resistance 2 Ohm are connected in turn (1) in series (2) in
parallel to a battery of 12 V. Calculate the ratio of power consumed in two cases.
6.
A piece of wire is redrawn by pulling it until its length is tripled. Compare the new
resistance with the original value.
7.
An electric kettle is rated 500W, 200V. IT is used to heat 400 gm of water for 30 secs.
Assuming the voltage to be 220V calculate the rise in temperature of water. Specific
heat capacity of water is 4200 J/Kg ºC.
8.
What is the resistance of a copper wire 20 meters long and 0.81 mm in diameter at 20°?
9.
A heater draws 1100 W at 220V. (a) Find the resistance of the heater (b) Calculate the
energy in KWh consumed in a week if the heater is used daily for 4 hours.
10.
The following three appliances are connected in series to a 120 V house circuit: a toaster,
1200 W; a coffee pot, 750 W; and a microwave, 6.0 × 102 W. If all were operated at the
same time, what total current would they draw?
11.
Three resistors with values of 3.0 Ω, 6.0 Ω, and 12 Ω are connected in series. What is
the
equivalent resistance of this combination?
12.
Three resistors with values of 4.0 Ω, 6.0 Ω, and 10.0 Ω are connected in parallel. What is
their equivalent resistance?
13.
Two resistors with values of 6.0 Ω and 12 Ω are connected in parallel. This combination is
connected in series with a 4.0 Ω resistor. What is the overall resistance of this
combination?
14.
A circuit contains a 1.5 volt battery and a bulb with a resistance of 3 ohms. Calculate the
current.
15.
Two resistors with values of 6.0 Ω and 12 Ω are connected in parallel. This combination is
connected in Series with a 2.0 Ω resistor and a 24 V battery. What is the current in the
2.0 Ω resistor?
16.
What is the equivalent resistance for the resistors in the figure below?
THS,VK, CL.X Physics Topic: Electricity Summer HHW Session:2013-14
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17.
What is the equivalent resistance for the resistors in the figure below?
18.
For the circuit shown below find the following,
a. What is the equivalent resistance for the resistors in the figure below?
b. What is the total voltage drop across the entire below circuit?
c. What is the total current in the circuit below?
20.
What would the current through the 2 ohm resistor in the figure below if 120V is
applied?
Long Answer questions (5 marks)
1.
State Ohms law with a neat circuit. Explain how this law can be verified and also plot the
expected v-I graph.
2.
(a)
Differentiate resistance and resistivity
(b)
the ratio of resistivities of two materials a and b is 1:2, ratio of their length is 3:4
and if the ratio of radii is 2:3 find the ratio of resistance of a and b.
Note: Submit the completed holiday home work by 7th July, 2013.
Name of Teacher: R.K. Sharma
THS,VK, CL.X Physics Topic: Electricity Summer HHW Session:2013-14
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