electricity

CBSE SCIENCE [class 10] Electricity Q1.What constitute electricity ? a. Free electrons in a conductor b. Battery c. cell d. Protons. Q2. S.I. unit of electric charge is a. Ampere b. Volt c. Columb d. Watt Q3.Potential difference between two points is a V= W/Q b. V= Q x W c. V=I x Q d. V= I/Q Q4.The volt metre used to measure potential difference is always connected in a. Series b. Parallel c. Both ways d.none Q5.The relation between potential difference & current across a conductor is a. R = V I b. V= I R c .I = V R d .V= P I Q6. Alloys are generally used in electrical heating devices because a. Have low melting point b. do not oxidize easily c. poor conductor of electricity . d. a & c both . Q7.When several resistors of are joined in series , the resultant resistance is a. Equal to the sum of their individual resistance b. Greater than any individual resistance c. More than sum of their individual resistance d. a & b . Q8.The commercial unit of electric energy is a. Joule b. Watt c. Volt d. k Watt h . Q 9.Resistivity of a material depends on a. Length of a wire b.Cross section area of wire c. mass of the wire d. None of these . Q10. To get least resistance from a number of resistors ,we connect a. All in series b. All in parallel c. Less resistors in series & more in parallel d. More resistors in series less in parallel . Q11.To distribute large current , we connect a number of resistance a. In series b. In parallel c. Half in series , half in parallel d. none Q12 .Resistance of a conductor a. Increases with increase in temperature b. decreases with temperature c. Independent of temperature d .Dependants on current Q13 Safety fuse wire is made of a.copper b. silver c. Alloy of Tin & Lead d. Platinum . Q14 .House hold electrical appliances are connected in a.Series b. Parallel c. Some in series ,some in parallel d. none Q15.Direction of flow of conventional current is taken from a.Negative to positive b. Positive to negative c. Any of the two d. None Q16. The device which measures electric current through a conductor , is called a. Ammeter b. Voltmeter c. Mano meter d. Water meter Q17.The law which gives a relation between electric potential difference and electric current is called a. Faraday’law b. oersted’ law c. Ohm’s law d. Newton’s law Q18.Heating effect of electric current is used in a.Voltmeter b.Ammeter c. Galvano meter d. Electric Geyser Q19.In the given circuit , ammeter reads 3 A,& Voltmeter reads 9V.The correct value of resistance R is a. Exactly 3 ohm b. Greater than 3 ohm c. Slightly less than 3 d. Zero . Q20 The slope of voltage [V] vs current [I] is called a. Resistance b. Resistivity c. Conductivity d. Conductance Q21. A fuse wire is always inserted in the a. Live wire b. In the neutral wire . C. In the earth line D. May be connected in any line . Q22 Two lamps of power 40 W & 60W are connected in parallel, the total power of combinations a. 40 W B. 60 W c.100 W d. 24 W. 23 .In a circuit containing two unequal resistors connected in parallel a.The current is same in both the resistance b. The current is large in the larger resistance c .The voltage is same across both the resistors . 24.In electric heating devices the material of the heating element is a.Brass b.Nichrome c. Silver d. Copper Q25.Rubber,Wood, Glass& porcelain are a. The best conductor b. The best insulator c. The best semiconductor d. All are super conductor . ANSWERS Q1.a Q2.c Q3.a Q4 b Q5.b Q6.b Q7.a Q8.d Q9.d Q.10 b Q11.b Q12.a Q13.c Q.14 b Q15.b Q16.a Q17.c Q18.d Q19.a Q20.a Q21.a Q22.c Q23.c Q24.b Q25.b