ELECTRICITY
CLASS: X
1. How many electrons constitute a current of(A) 6.25 × 1018 (B) 6.25 × 1012 (C) 6.25 × 1011 (D) 6.25
2. 1 Coulomb is equal to :
(A) 1 amp × 1 sec (B) 1 amp / 1 sec (C) 1 joule × 1 amp (D) 1 joule / 1 sec
3. When a body is negatively charged by fraction, it means :
(A) the body has acquired excess of electrons (B) the body has acquired excess of protons
(C) must be zero (D) many be negative or positive or zero
4. If a charged body attracts another body, the charge on the other body :
(A) must be negative (B) must be positive
(C) must be zero (D) may negative or positive or zero
5. A suitable unit for expressing the strength of electric field is :
(A) V/C (B) C/m (C) N/C (D) C/N
6. One ampere equal ____________
7. What constituted current in a metal wire ?
(A) Electrons (B) Protons (C) Atoms (D) Molecules
8. If I is the current through a wire and e is the charge of electron, then the number of electrons in t seconds
will be given by-
(A)Ie/t (B) e/lt (C) lt/e (D) lte
9. Conventionally, the direction of the current is taken as -
(A) the direction of flow of negative charges (B) the direction of flow of atoms
(C) the direction of flow of positive charges (D) the direction of flow of molecules
10. When the temperature of metallic conductor is increased its resistance :
(A) always decrease (B) always increase
(C) may increase or decease (D) remain the same
11. Specific residence of a wire depends upon :
(A) its length (B) its cross - sectional area (C) its dimensions (D) its material (E) none of these
12. The unit of resistivity is :
(A) ohm (B) ohm meter (C) ohm /meter (D) none of these
13. A wire of resistance R is cut into t equal parts. These parts are then connected in parallel. The equivalent resistance of combination will be :
(A) tR (B) R/t (C) t/R (D) none of these
14 A piece of wire having resistance 4 ohm is bent through 180 at its mid point and the two halves are twisted together, then resistance is :
(A) 1 ohm (B) 2 ohm (C) 5 ohm (D) 8 ohm (E) none of these
15. Three resistance each of 8 ohm are connected to a triangle. The resistance between any two terminal will be:
(A) 12 ohm (B) 2 ohm (C) 6 ohm (D) 3/16 ohm (E) none of these
16. In how many parts(equal) a wire of 100 ohm be cut so that a resistance of 1ohm is obtained by connecting them in parallel ?
(A) 10 (B) 5 (C) 100 (D) 50 (E) none of these
17. The filament of an electric bulb is made of tungsten because :
(A) its melting point is high (B) it is cheaper (C)its resistance is negligible (D) its filament is easily made (E) none of these
18. If a wire of resistance 1 ohm is stretched to double its length, then the resistance will become :
(A) ½ ohm (B) 2 ohm (C) ¼ ohm (D) 4 ohm (E) none of these
19. Rate of heat generated by electrical current in a resistive circuit is expressed in :
(A) IR^2 (B) IR (C) I^2R (D) IR (E) none of these
20. Two heater wires of equal length are first connected in series and then in parallel with a battery. They ratio of heat produced in the two cases in :
(A) 2 : 1 (B) 1 : 2 (C) 4 : 1 (D) 1 : 4 (E) none of these
21. How much electrical energy in kilowatt hour is consumed in operating ten, 50 watt bulbs for 10 hours per day in a month of 30 days ?
(A) 15 (B) 150 (C) 1500 (D) 15000 (E) none of these
22. An electric iron draws a current of 4A when connected to a 220 V mains. Its resistance must be :
(A) 40 ohm (B) 55 ohm (C) 100 ohm (D) None of these (E) none of these
23. The resistance of a conductors is reduced to half its initial value. In during so the heating effects in the conductor will become :
(A) half (B) one-fourth (C) four times (D) double (E) none of these
24. Laws of heating are given by :
(A) Faraday (B) Joule (C) Ohm (D) Maxwell
25. An electric iron is based upon the principle of :
(A) magnetic effect of current (B) heating effect of current
(C) chemical effect of current (D) none of these
26. A fuse wire is always connected to the :
(A) neutral wire (B) earth wire (C) live wire (D) none of these (E) none of these
27. Heating effete of a current conductor is due to :
(A) Attraction between electrons and atoms (B) Loss of kinetic energy of moving electrons
(C) Loss of kinetic energy of moving atoms (D) Repulsion between electrons and atoms (E) none of these
28. The wire having a red plastic covering is a :
(A) live wire (B) neutral wire (C) earth wire (D) all of these (E) none of these
29. A switch is always connected to the
(A) earth wire (B) neutral wire (C) live wire (D) all of these (E) none of these
30. The wire having a black plastic covering is a
(A) live wire (B) neutral wire (C) earth wire (D) all of these (E) none of these
31. The wire having a green plastic covering is a
(A) live wire (B) neutral wire (C) earth wire (D)all of these (E) none of these
32. In three pin socket (shoe) the bigger hole is connected to :
(A) any wire (B) live wire (C) neutral wire (D) earth wire (E) none of these
33. Coming of live wire and neutral wire in direct contact cause :
(A) short-circuiting (B) over loading (C) no damage (D) unknown effect (E) none of these
34. In electric fitting in a house :
(A) the earth wire goes through the switch (B) the neutral wire goes through the switch
(C) the live wire goes through the switch (D) no wire goes through the switch (E) none of these
35. High power electrical appliances are earthed to
(A) avoid shock (B) avoid wastage (C) Make the appliance look beautiful (D) unknown effect (E) none of these
No comments:
Post a Comment