| 41 |
A bulb lights up almost instantly when switched on, although the drift speed of electrons is very small. This… |
Physics
Electric current and drift velocity |
Easy |
| 42 |
A steady current flows through a wire whose radius at end X is twice the radius at end Y. The ratio of drift … |
Physics
Electric current and drift velocity |
Hard |
| 43 |
The resistance of a copper wire of length 10 m and cross-section 1 mm² (ρ = 1.7 × 10⁻⁸ Ω m) is: |
Physics
Ohm’s law and resistance |
Easy |
| 44 |
A uniform wire is stretched to twice its original length. Its resistance becomes: |
Physics
Ohm’s law and resistance |
Medium |
| 45 |
The resistivity of a metal wire depends on: |
Physics
Ohm’s law and resistance |
Easy |
| 46 |
A metal wire has resistance 10 Ω at 0 °C and temperature coefficient 0.004 °C⁻¹. Its resistance at 100 °C is: |
Physics
Ohm’s law and resistance |
Medium |
| 47 |
As the temperature of a pure semiconductor rises, its resistivity: |
Physics
Ohm’s law and resistance |
Hard |
| 48 |
The resistance of the filament of a bulb rated 100 W, 220 V is: |
Physics
Electrical energy and power |
Easy |
| 49 |
A 100 W, 220 V bulb is connected to a 110 V supply. Assuming constant resistance, it consumes: |
Physics
Electrical energy and power |
Medium |
| 50 |
A 1000 W heater is used for 3 hours. The energy consumed is: |
Physics
Electrical energy and power |
Easy |
| 51 |
One kilowatt-hour is equal to: |
Physics
Electrical energy and power |
Medium |
| 52 |
Electric power is transmitted over long distances at very high voltage mainly because: |
Physics
Electrical energy and power |
Hard |
| 53 |
A cell of emf 2 V and internal resistance 0.5 Ω is connected to a 3.5 Ω resistor. The terminal voltage is: |
Physics
Cells, emf and internal resistance |
Easy |
| 54 |
Three identical cells, each of emf 1.5 V and internal resistance 0.5 Ω, are joined in series across a 3 Ω res… |
Physics
Cells, emf and internal resistance |
Medium |
| 55 |
Two identical cells, each of emf 2 V and internal resistance 1 Ω, are joined in parallel across a 1.5 Ω resis… |
Physics
Cells, emf and internal resistance |
Medium |
| 56 |
The terminal voltage of a cell equals its emf when: |
Physics
Cells, emf and internal resistance |
Easy |
| 57 |
A cell of emf E and internal resistance r is being charged by a current I. Its terminal voltage is: |
Physics
Cells, emf and internal resistance |
Hard |
| 58 |
Kirchhoff’s junction rule is a consequence of the conservation of: |
Physics
Kirchhoff’s rules and the Wheatstone bridge |
Easy |
| 59 |
Kirchhoff’s loop rule is based on the conservation of: |
Physics
Kirchhoff’s rules and the Wheatstone bridge |
Easy |
| 60 |
In a Wheatstone bridge, P = 10 Ω, Q = 20 Ω and R = 15 Ω. For balance, S must be: |
Physics
Kirchhoff’s rules and the Wheatstone bridge |
Medium |