CBSE
Multiple Choice QuestionsOne kg of copper is drawn into a wire of 1 mm diameter and a wire of 2 mm diameter. The resistance of the two wires will be in the ratio
2 : 1
1 : 2
16 : 1
4 : 1
Short Answer TypeTwo wires each of same material and same length have 2 : 1 ratio of their radii. If the first wire has a resistance of 2 Ω then what will be the equivalent resistance of the two wires when they are connected in series ?
Multiple Choice QuestionsResistors P and Q are connected in the gaps of the meter bridge. The balancing point is obtained m from the zero end. If a 6 Ω resistance is connected in series with P the balance point shifts to m from the same end. P and Q are
4, 2
2, 4
both (a) and (b)
neither (a) nor (b)
A battery of e.m.f. E and internal resistance r is connected to an external resistance R the condition for maximum power transfer is
r < R
r > R
r = 1/R
r = R
Short Answer TypeWhat should be the resistance of an ideal ammeter and an ideal voltmeter ?
Multiple Choice QuestionsA milliammeter of range O - 30 mA has internal resistance of 20Ω.The resistance to be connected in series to convert it into a voltmeter of maximum reading 3V is
49 Ω
80 Ω
40 Ω
30 Ω
Short Answer TypeA wire of length 5 m is stretched by 1 mm by a force of 1 N. What is the value of energy stored in the wire ?
A 60 W- 220 V bulb is connected in series with another bulb 40 W-220 V. Which bulb will give more illuminance ?
Multiple Choice QuestionsThe currents i1 and i2 through the resistors R1 = 10 Ω and R2 = 30 Ω in the circuit diagram with E1 = 3 V , E2 = 3 V and E3 = 2 V are respectively
0.2 A, 0.1 A
0.4 A, 0.2 A
0.1 A, 0.2 A
0.2 A, 0.4 A
A thin wire of resistance 4Ω is bent to form a circle. The resistance across any diameter is
4 Ω
2 Ω
1 Ω
8 Ω
