Choose the correct alternatives and rewrite the complete sentences
*1. 1mA = ..................... .
(a) 103 A (b) 10-3 A (c) 106 A (d) 10-3 A
*2. To increase the effective resistance in a circuit the resistors are connected in ..................... .
(a) series (b) parallel (c) series and parallel (d) non of these
*3. 1 kilowatt hr = ..................... .
(a) 4.6 × 106 joule (b) 3.6 × 106 joule (c) 30.6 × 106 joule (d) 3.6 × 105 joule
*4. The current passing through a 3 Ω resistor if P.D. of 12V is applied across it is ............... .
(a) 36 A (b) 4 A (c) 0.25 A (d) 15 A
5. The S.I. unit of potential difference is ..................... .
(a) ampere (b) volt (c) ohm (d) joule
6. The unit of electric charge is ..................... .
(a) ampere (b) coulomb (c) volt (d) ohm
7. One ..................... is the potential difference when one joule of work is
done to move a charge of one coulomb.
(a) ohm (b) coulomb (c) volt (d) ampere
8. The S.I. unit of electric current is .............. .
(a) ampere (b) coulomb (c) volt (d) ohm
9. According to Ohm’s law, longer the length of wire, ..................... is the
resistance for given cross section of wire.
(a) lower (b) greater (c) zero (d) constant
10. A substance which does not allow charges to pass through it, easily is
called as ..................... .
(a) metal (b) conductor (c) insulator (d) semiconductor
11. If a current of 0.1 A is passed through a wire of resistance 20 ohm, the
potential difference across the wire is ..................... .
(a) 20 ohm (b) 20 volt (c) 10 volt (d) 2 volt
12. Electric current is measured with the help of a device called ..................... .
(a) an ammeter (b) a volt meter (c) a thermometer (d) a calorimeter
13. The equivalent resistance of a parallel combination is ..................... than
each of the individual resistance.
(a) greater (b) smaller (c) stronger (d) more
14. If two resistances of 10 ohm and 15 ohm are connected in parallel the equivalent resistance will be ..................... ohm.
(a) 25 (b) 6 (c) 1/6 (d) 150
15. In conductors, electrons are always in the state of ..................... motion.
(a) lower to higher (b) opposite (c) similar (d) random
16. A diagram which indicates how different components in a circuit have
been connected by using the electrical symbols for the components is called............ .
(a) ray diagram (b) component diagram (c) venn diagram (d) circuit diagram
17. The electrons flow from negative terminal to positive terminal of the cell but the ..................... of current is from positive terminal to negative terminal of the cell.
(a) conventional direction (b) electron current (c) real current (d) negative
18. The SI unit of resistivity is ..................... .
(a) ohm–metre (b) ohm-(metre)2 (c) ohm (d) joule
19. When potential dif ference is applied between two ends of a wire ................ in it.
(a) heat is produced (b) charge is set up (c) charge move randomly (d)
electrons move randomly
20. The quantity of heat produced depends upon ..................... .
(a) square of the current (I2)
(b) resistance of the conductor (R)
(c) time for which the current flows (t)
(d) I2Rt
21. 1 cal = ..................... joule.
(a) 107 (b) 105 (c) 41.8 (d) 4.18
22. Heat energy produced is expressed in terms of ..................... .
(a) calorie (b) newton (c) ampere (c) coulomb
23. Tungsten in bulb has ..................... .
(a) high melting point (b) high charge (c) high P.D. (d) high insulation
24. Fuse is made up of ..................... .
(a) iron and carbon (b) lead and Tin (c) copper and Zinc (d) copper and Aluminum
25. The ..................... in the fuse is such that it melts when a current passing through it exceed a certain value.
(a) length (b) diameter (c) charge (d) distance
26. In surgery finely heated ..................... wire is used for cutting tissues
much more efficiently than a knife.
(a) tungsten (b) lead and tin (c) platinum (d) iron
27. The charge of an electron is ................... .
(a) 1.6 × 10–19 C (b) 1.6 × 10–32 C (c) 1.6 × 10–19 A (d) 1.6 × 10–32 V
28. 1 µ A (micro-ampere) = ..................... .
(a) 10–5 A (b) 10–6 A (c) 10–3 A (d) 10–2 A
29. ..................... is the electric discharge travelling from clouds at high
potential to the earth.
(a) Lightning (b) Tornado (c) Thunder (d) Sparks
30. The resistivity of ..................... is the highest in conductors.
(a) nickel (b) mercury (c) chromium (d) manganese
A. Answers.
1. 10-3 A
2. Series
3. 3.6 x 106 joule
4. 4A
5. Volt
6. Coulomb
7. Volt
8. Ampere
9. Greater
10. Insulator
11. 2 volt
12. An ammeter
13. Smaller
14. 6
15. Random
16. Circuit diagram
17. Conventional direction
18. Ohm – metre
19. Heat is produced
20. I2Rt
21. 4.18
22. Calorie
23. High melting point
24. Lead and tin
25. Diameter
26. Platinum
27. 1.6 x 10-19C
28. 10-6A
29. Lightning
30. Mercury
