Central Board of Secondary Education (CBSE)
Sample Paper – 2012
Class – X
Subject – Science
(Electricity and Magnetism)
1. Power does not exit
(a) I2R (b) VR2 (c) VI (d) V2/R
2. Unit of Ele. Power is
(a)Kwh (b) Kw (c) Ohms meter (d) Joule
3. A wire of resistance R is converted into loop (circle) what will be the total resistance if it is connected in circuit? (a) R/2 Ω (b) R/3 Ω (c) R/4 Ω (d) R/6Ω
4. An electron enters a magnetic field at right angles to it, as shown in fig. The direction of the force acting on the electron will be To Right (b) To Left (c) Out of the page (d) inside the page
5. The commercial unit of electric energy is
(a)Kwh (b) Kw (c) Ohms meter (d) Joule
6. One kilowatt hour is equal to
(a) 3.6 x 106j (b) 6.3 x 106j (c) 3.6 x105j (d) 6.3 x 105 Joule
7. Find total resistance in the fig.
(a) 9Ω (b) 16Ω (c) 3Ω (d) 1/2Ω
8. A Volta meter is always arrange in the circuit
(a) Series (b) parallel (c) non of these (d) any way
9. Voltage is always remains constant in (a) Series (b) parallel (c) non of these
10. Explain 1Volt Pot. Difference?
11. Define Resistance? What factors affect the resistance? Relate these factors with resistance
12. How much energy is given to each coulomb of charge passing through a 6 v battery?
13. Explain Ohm’s law. Draw its graph.
14. What do you mean by Resitivity? Find its units.
15. element of electric iron made by alloy rather than pure metal? What is reason behind it?
16. What is Differentiate between short circuiting and overloading of electrical circuits. How a fuse does protect an electrical circuit?
17. Derive the combining resistance when R1. R2, R3 are combined in series as well as in parallel.
18. Find in this figure
(a) Total current flow in each resistance in the circuit.
(b) Total resistance in the circuit
19. How can 2Ω, 3Ω, and 6Ω are connected to give total resistance of (a) 4Ω (b) 1Ω
20. A desert cooler of 400watt operated 8 hours per day. What is cost of energy to operate it for the month of Nov. @ Rs. 4 per unit?
21. Several electric bulbs designed to be used on a 220V electric supply line are rated 100W. How many lamps can be connected in parallel with each other across the two wires of 220V line if the maximum allowable current is 5A?
22. Two lamps, one rated 100 W at 220 V, and the other 60W at 220 V, are connected in parallel to electric mains supply. What current is drawn from the line if the supply voltage is 220V?
23. 100J of heat is produced each second in a 4Ω resistance, Find the potential difference across the resistor?
24. A wire of four meter has resistance 12 ohms is divided in to four equal parts. What will be the
(a) Resistance of each part (b) Resistivity of each part
25. In a household electric circuit different appliances are connected in parallel to one another. Give two reasons
26.A coil of insulated copper wire is connected to a galvanometer. What will happen if a bar magnet:
(a) Pushed into the coil
(b) Withdrawn from inside the coil
(c) Held stationary inside the coil.
27.Explain Right Hand Thumb rule to find the direction of the magnetic field around a current carrying straight conductor. How will this magnetic field be affected on?
(a) Increasing the electric current through the conductor
(b) Changing the direction of flow of current in the conductor
28. Three wires are labeled as shown below
i. Identify A, B and C
ii. Overloading is said to occur when two of the above wires meet. Which are they? iii. What happens to the current in the circuit when the above condition occurs
29.Draw the magnetic field due to a current through a circular loop .Compare the pattern of the field with the magnetic field around a bar magnet .Are they similar, justify your answer.
30. How will you explain – the phenomena of electromagnetic induction in one – coil when current passing through a neighboring coil increase or decrease?
Sample Paper / Model Test Paper CBSE 12th 2012