FIRST SEMESTER 2017-2018
GRADE : X
PHYSICS WORKSHEET -1 (ELECTRICITY )
_________________________________________________________________________________________________________
1. What length of a copper wire of cross-sectional area 0.01 mm2 would be required
to obtain a resistance of 1kΩ? Resistivity of Cu = 1.7 X 10-8 Ω m. ( Ans : 588.2 m )
2. A metal wire of specific resistance 64 X 10-6 Ω m and length 1.98 cm has a
resistance of 7Ω. Find its radius.
( Ans : 0.024 cm )
3. Calculate the resistance of a 2m long nichrome wire of radius 0.321 mm. Resistivity
of nichrome is 15 x 10-6 Ω m .If a P.D of 10 V is applied across this wire, what will
be the current in the wire?
( Ans : 9.26 Ω , 1.08 A )
4. A wire of resistance 10 Ω is drawn out so that its length is thrice its original
length. Calculate its new resistance.
( Ans : 90 Ω )
5. A copper wire has a diameter 0.5 mm and resistivity 1.6x10-8 Ω meter. What will be
the length of the wire to make the resistance 12 Ω? How much will be the
resistance of another copper wire of same length but half the diameter?
(Ans:143.7m, 48 Ω)
6. Draw schematic diagrams of an electric circuit comprising of 3 cells and an electric
bulb, ammeter, plug key in the ON mode and another with same components but
with two bulbs in parallel and a voltmeter across the combination
7. A 9 ohm resistor is cut into three equal parts and connected in parallel. Find
the equivalent resistance of the combination. (ans 1 ohm)
8. Consider the following circuit diagram. If R1=R2=R3=R4=R5=3Ω, find the
equivalent resistance of the circuit. (Ans : 8 ohm)
9.A wire of resistance 5 ohms is bent in the form of a closed circle.. what is the effective
resistance between.the two points at ends of any diameter of the circle ? (ans : 1.25 Ω )
10.A torch bulb is rated 2.5Vand 750mA. Calculate a) its power, b) its resistance and c)
the energy consumed, if this bulb is lighted for 4 hours.
(Ans : a)1.875W, b)3.33Ω, c)7.5Wh )
11. Five resistors are connected in a circuit as shown. Find the ammeter reading when
circuit is closed. (Ans : 1A)
12. Study the circuit shown in which three identical bulbs B1, B2 and B3 are
connected in parallel with a battery of 4.5V.
a. What will happen to the glow of other 2 bulbs if the bulb B3 gets fused?
b. If the wattage of each bulb is 1.5W, how much reading will the ammeter
A show when all the three bulbs glow simultaneously? (Ans: 1 Ampere)
c. Find the total resistance of the circuit. (Ans: 4.5 Ω)
13. .Two resistors , with resistances 5 Ω, 10 Ω respectively are to be connected to a
battery of emf 6 V so as to obtain :
i)
ii)
a) Minimum current flowing.
b) Maximum current flowing
How will you connect the resistances in each cases?
Calculate the strength of the total current in the circuit in the two cases ?
( ans : o.4A and 1.8 A)
***********************************
Thank you for using www.freepdfconvert.com service!
Only two pages are converted. Please Sign Up to convert all pages.
https://www.freepdfconvert.com/membership