CLASS-10
ELECTRICITY
MCQ
  1. The resistivity of a given metallic wire depends upon
  1. its length                            c) its thickness
  2. its shape                             d) nature of material
  1. If three resistances of 3ohm each are connected in parallel,what will be there total resistance?
  1. 3 ohm                                  c) 1 ohm
  2. 1/3 ohm                              d) 0.5 ohm
  1. A wire that has resistance R is cut into two equal pieces. The two parts are joined in parallel. What is the resistance of the combination?
  1. R/2                                        c) R/4
  2. R/3                                        d) R/6
  1. Which of the following terms does not represent electrical power in a circuit?
  1. V*I                                          c) I2R
  2. V2/R                                        d) IR2
  1. Unit of electrical power is
  1. Volt Amphere                       c) watt second
  2. Kilowatt hour                        d) joule second
  1. What is the maximum resistance which can be made using five resistors each of 1/5 ohm?
  1. 1/5 ohm                                  c) 5 ohm
  2. 10 ohm                                    d) 1 ohm
  1. An electric bulb draws a current of 0.2 A when it operates at 220 V. Calculate the amount of electric charge flowing through it in 1 h.
  1. 720 Coloumb                       c)  420 Coloumb
  2. 360 Coloumb                         d)  1000 Coloumb
  1. An electric iron is rated 2 kW at 220 V. Calculate the capacity of the fuse that should be used for the electric iron.
  1. 20 A                                      c) 0.25 A
  2. 10 A                                      d) 100 A
  1. A metallic conductor has loosely bound electrons called free electrons. The metallic conductor is
  1. Negatively charged                 c) neutral
  2. Positively charged                   d) a and b both
  1. If in the given arrangement, the three resistors are to be replaced by a single resistor. What will be the value of this resistor?
https://www.jagranjosh.com/imported/images/E/Articles/sci-ch12-image1.png
  1. 4 ohm                                    c) 9 ohm
  2. 6 ohm                                     d) 18 ohm
  1. The potential difference across the 3 Ω resistor in the following diagram is:
https://www.jagranjosh.com/imported/images/E/Articles/sci-ch12-image2.png
  1. 1/9 V                                    c) 6 ohm
  2. 1/2 V                                    d) 1 ohm
  1. Two appliances of rating 200 watt-250 volts and 100 watt-250 volts are joined in series to a 250 volts supply. Total power consumed in the circuit is
  1. 46 watt                          c) 56 Watt       
  2. 67 Watt                          d) 72 Watt
  1. Two electric bulbs have resistances in the ratio 1:2. If they are joined in series, the energy consumed in
Them in the ratio:
       (a) 2:1                                  c) 4:1
       (b) 1:2                                  d) 1:1
14. If the current flowing through a fixed resistor is halved, the heat produced in it will become
         a) one fourth                      c) double
b) one half                          d) four times
15. In the given figure, the resistors
https://www.jagranjosh.com/imported/images/E/Articles/sci-ch12-image4.png
(a) 6 Ω, 3 Ω and 9 Ω are in series
(b) 9 Ω and 6 Ω are in parallel and the combination is in series with 3 Ω
(c) 3 Ω, 6 Ω and 9 Ω are in parallel
(d) 3 Ω and 6 Ω are in parallel and the combination is in series with 9 Ω
16.   The purpose of a rheostat is:
(a)  Increase the magnitude of current only
(b)  Decrease the magnitude of current only
(c)  Increase or decrease the magnitude of current
(d)  None of these
17.Point to be kept in mind for verification of Ohm’s Law is:
(a)  Ammeter and voltmeter should be connected in series
(b)  Ammeter should be connected in series and voltmeter in parallel
(c)  Ammeter should be connected in parallel and voltmeter in series
(d)  Ammeter and voltmeter should be connected in parallel
18 . When a 40V battery is connected across an unknown resistor there is a current of 100 mA in the circuit. Find the value of the resistance of the resister:
(a)  5000 Ω
(b)  400 Ω
(c)  0.8 Ω
(d)  none of these
19. A battery of 6V is connected in series with resisters of 0.1 ohm , 0.15 ohm,0.2 ohm,0.25 ohm and 6 ohm. How much current would flow through the 0.3 ohm resistor?
(a)  0.895A
(b)  2.22A
(c)  1A
(d)  none of these
20.  A fuse wire is inserted in a?
(a)  . Live wire
(b)  . In the neutral wire
(c)  . In the earth wire
(d)  . May be connected in any line.
 
 
Answers
  1. D
  2. C
  3. C
  4. D
  5. A
  6. D
  7. A
  8. B
  9. C
  10. C
  11. D
  12. B
  13. B
  14. A
  15. D
  16. C
  17. B
  18. B
  19. D
  20. A
Short questions- answers
  1. By what other name is the unit joule/coloumb called?
  2. Fill in the blanks: potential difference is measured in____ by using a_____ placed in____ across component.
  3. Define electric charge.
  4. Keeping the potential difference constant, the resistance of a circuit is halved. By how much does the current change?
  5. Give the symbols of (i) an electric cell     (ii) rheostat
  6. What is the shape of V-I graph for a metallic wire?why?
  7. The resistance of a resistor is kept constant and the potential difference across its two ends is decreased to half of its former value. State the change that will occur in the current flowing through it.
  8. Draw schematic diagram of an electric circuit consisting of a battery of two cells each of 1.5 V,5 ohm,10 ohm and 15 ohm resistors and a plug key, all connected in series.
  9. Name the instrument used to measure (i) current in circuit    (ii) potential difference between two ends.
  10. Why do electricians wear rubber hand gloves while working?
  11. Would you connect a fuse in series or in parallel to an electric circuit?
  12. Nichrome is used to make the element of an electric heater. Why ?
  13. How many joules are equal to 1 kWh?
  14. The voltage- current(V-I) graph of a metallic circuit at two different temperature T1 and T2 is shown in the figure. Which of the two temperatures is higher and why?

     
 

 
 
  1.  State joules law of heating.
  2. Calculate the effective resistance of the circuit.
  1. The length of a wire is doubled and its area of cross section is also doubled. What is the change in resistivity?
  2. In which arrangement series or parallell, are various electrical devices connected in the domestic lightening circuit?
  3. Distinguish between an open and closed circuit.
  4. A T.V. set shoots out a beam of electrons. The beam current is 10 ---5 A. how many electrons strike the T.V. screen in each second? How much charge strikes the screen in a minute?
  5. Calculate the resistance of an electric bulb which allows a 10 A current when connected to a 220 V power source.
  6. An electric iron has a rating of 750 W,220 V. calculate (i) current passing through it  (ii) its resistance when in use
  7. An electric kettle of 2 kW works for 2 hour daily. Calculate (i) energy consumed in S.I. and commercial unit,  (ii) cost of running it in the month of june at the rate of rupees 3.00 per unit.
  8. Why coils of electric appliances is made up of an alloy rather than a pure metal?
  9. Find out the following in the electric circuit given:
  1. Effective resistance of two 8 ohm resistors in combination
  2. Current flowing through 4 ohm resistance
  3. Potential difference across 4 ohm resistor
  4. Power dissipated in 4 ohm resistor
  5. Difference in ammeter readings, if any.