A cell, a resistor, a key and ammeter are arranged as shown in the circuit diagrams of Figure 12.1. The current recorded in the ammeter will be
maximum in (i)
maximum in (ii)
maximum in (iii)
the same in all the cases
In the following circuits (Figure 12.2), heat produced in the resistor or combination of resistors connected to a 12 V battery will be
same in all the cases
minimum in case (i)
maximum in case (ii)
maximum in case (iii)
Electrical resistivity of a given metallic wire depends upon
its length
its thickness
its shape
nature of the material
A current of 1 A is drawn by a filament of an electric bulb. Number of electrons passing through a cross section of the filament in 16 seconds would be roughly
1020
1016
1018
1023
Identify the circuit (Figure 12.3) in which the electrical components have been properly connected.
(i)
(ii)
(iii)
(iv)
What is the maximum resistance which can be made using five resistors each of 1/5 Ω?
1/5 Ω
10 Ω
5 Ω
1 Ω
What is the minimum resistance which can be made using five resistors each of 1/5 Ω?
1/5 Ω
1/25 Ω
1/10 Ω
25 Ω
The proper representation of series combination of cells (Figure 12.4) obtaining maximum potential is
(i)
(ii)
(iii)
(iv)
Which of the following represents voltage?
Work done / (Current × Time)
Work done × Charge
(Work done × Time) / Current
Work done × Charge × Time
A cylindrical conductor of length \(l\) and uniform area of cross-section \(A\) has resistance \(R\). Another conductor of length \(2l\) and resistance \(R\) of the same material has area of cross section
A/2
3A/2
2A
3A
A student carries out an experiment and plots the V–I graph of three samples of nichrome wire with resistances \(R_1, R_2\) and \(R_3\) respectively (Figure 12.5). Which of the following is true?
\(R_1 = R_2 = R_3\)
\(R_1 > R_2 > R_3\)
\(R_3 > R_2 > R_1\)
\(R_2 > R_3 > R_1\)
If the current \(I\) through a resistor is increased by 100% (assume that temperature remains unchanged), the increase in power dissipated will be
100 %
200 %
300 %
400 %
The resistivity does not change if
the material is changed
the temperature is changed
the shape of the resistor is changed
both material and temperature are changed
In an electrical circuit three incandescent bulbs A, B and C of rating 40 W, 60 W and 100 W respectively are connected in parallel to an electric source. Which of the following is likely to happen regarding their brightness?
Brightness of all the bulbs will be the same
Brightness of bulb A will be the maximum
Brightness of bulb B will be more than that of A
Brightness of bulb C will be less than that of B
In an electrical circuit two resistors of 2 Ω and 4 Ω respectively are connected in series to a 6 V battery. The heat dissipated by the 4 Ω resistor in 5 s will be
5 J
10 J
20 J
30 J
An electric kettle consumes 1 kW of electric power when operated at 220 V. A fuse wire of what rating must be used for it?
1 A
2 A
4 A
5 A
Two resistors of resistance 2 Ω and 4 Ω when connected to a battery will have
same current flowing through them when connected in parallel
same current flowing through them when connected in series
same potential difference across them when connected in series
different potential difference across them when connected in parallel
Unit of electric power may also be expressed as
volt ampere
kilowatt hour
watt second
joule second