Assignment of Chapter 12: ELECTROMAGNETISM

ASSIGNMENT

CHAPTER # 12

CURRENT ELECTRICITY

 

1. 1x10⁷ electrons pass through a wire in 1μs. The current through the wire will be:  

a) 1.6x10^-6A b) 1.6x10^-6A c) 1.6x10^-6A d) 1.6x10^-6A  Reason/Hints________________________________________________________________

 

2. The heat produced by a current in a wire of resistance R is:  

a) H = I²/Rt b) H = IR²t c) H = I²Rt d) H = Rt/I Reason/Hints_____________________________________________________________

 

3. The terminal potential difference of a cell is given by:  

a) V = E/R+r b) V = E/IR c) V = E-IR d) None of these  Reason/Hints_______________________________________________________

 

4. The reciprocal of resistance is called:  

a) Reluctance b) Acceptance c) Conductance d) Inductance Reason/Hints____________________________________________________________ 

 

           5. A wire of 9Ω is bent to form an equivalent triangle. Its equivalent resistance across one of  the side will be:  

a) 2Ω b) 5Ω c) 27Ω d) 3Ω 

Reason/Hints____________________________________________________________ 

 

           6. A neon flash light cell with an emf of 1.5V gives a current of 15A when connecting  directly to an ammeter of resistance 0.04ohm. Internal resistance of the cell is: 

          a) 0.004ohm b) 0.06ohm c) 0.10ohm d) 0.13ohm Reason/Hints___________________________________________________________________

 

7. Temperature coefficient for thermistor is:__________  

a) Always Negative b) Always Positive c) Changing from positive to negative and vice versa d) May be positive or may be  negative 

Reason/Hints____________________________________________________________

 

           8. Resistance of two lamps is in the ratio 4:5. Which of the following is the ratio of their  powers when operated on the same voltage?  

a) 4:5 b) 5:4 c) 16:25 d) 25:16 

Reason/Hints_____________________________________________________________

 

9. What is measured by the energy displaced when a source drives a unit charge round a  complete circuit?  

a) Electromotive force b) Potential difference c) Power d) Resistance Reason/Hints_____________________________________________________________

 

10. What is the order of drift velocity?  

            a) 10^-1m.s^-1 b) 10^-5m.s^-1 c) 10^-3m.s^-1 d) 10⁶m.s^-1 Reason/Hints___________________________________________________________________

 

11. What is the length of the wire having resistance “R”, diameter “d” and resistivity of the  material “ρ”?  

a) d²R/4ρ b) 4πρR/d² c) 4R/πρd² d) πd²R/4ρ Reason/Hints_____________________________________________________________

 

12. Which of the following quantities has the unit Siemen?  

a) Resistance b) Resistivity c) Conductance d) Conductivity  \

Reason/Hints_____________________________________________________________

 

13. It is required to increase the current to double in a circuit of total resistance R. For this  purpose resistance Rx is connected to R then:______________  

a) Rx = R/2, (Rx in parallel to R) b) Rx = R, (Rx in parallel to R) c) Rx = R/2, (Rx in series to R) d) Rx = 2R, (Rx in series to R) Reason/Hints_____________________________________________________________

 

14. Kirchhoff’s second rule (loop rule) for electric circuit is essentially based on  ____________ in electric circuit:  

 a) Conservation of energy b) Conservation of charge   c) Conservation of temp. d) Conservation of resistance 

Reason/Hints___________________________________________________________________

 

15. The amount of heat is the produced in a resistor when a current is passed through it, can  be found by using:  

a) Faraday’s law b) Lenz’s law c) Joule’s law d) Kirchhoff’s law

Reason/Hints____________________________________________________________

 

16. Terminal potential difference of a battery of internal resistance r and electromotive force  ε.  

a) Vt = ε + Ir b) Vt =ε – Ir c) Vt = ε – r / r d) Vt =ε - r / I Reason/Hints_____________________________________________________________

 

17. Which electric bulb has least resistance?  

a) 60watts b) 100watts c) 200watts d) 500watts  Reason/Hints____________________________________________________

 

18. A light bulb is marked 60watt 120volt, its heated resistance is:_____________ 

a) 60Ω b) 120Ω c) 180Ω d) 240Ω Reason/Hints__________________________________________________________

 

19. If the temperature of a conductor is increased, the product of resistivity and conductivity: 

a) Increased b) Decrease c) Remain constant d) May increase or decrease Reason/Hints___________________________________________________________________

 

 Answers will be published soon!