What is the average drift speed of conduction electrons in a copper wire of cross-sectional area 1.0×10-7 m2 carrying a current of 1.5 A? Assume that each copper atom contributes roughly one conduction electron. The density of copper is 9.0×103 kg/m3, and its atomic mass is 63.5 u.
1. 1.1 mm s-1
2. 2.1 mm s-1
3. 3.1 mm s-1
4. 4.1 mm s-1
An electric toaster uses nichrome for its heating element. When a negligibly small current passes through it, its resistance at room temperature (27.0 °C) is found to be 75.3 Ω. When the toaster is connected to a 230 V supply, the current settles, after a few seconds, to a steady value of 2.68 A. What is the steady temperature of the nichrome element? The temperature coefficient of resistance of nichrome averaged over the temperature range involved is 1.70 × 10–4 °C–1
1. 8270 C
2. 8200 C
3. 8470 C
4. 8000 C
The resistance of the platinum wire of a platinum resistance thermometer at the ice point is 5 Ω and at the steam point is 5.23 Ω. When the thermometer is inserted into a hot bath, the resistance of the platinum wire is 5.795 Ω. The temperature of the bath is:
1. 300.200C
2. 345.650C
3. 320.200C
4. 400.120C
A network of resistors is connected to a 16 V battery with an internal resistance of 1Ω, as shown in the figure. The equivalent resistance of the network is:
1. 4Ω
2. 5Ω
3. 7Ω
4. 2Ω
A network of resistors is connected to a 16 V battery with an internal resistance of 1 Ω, as shown in the figure. The current in 1 Ω resistor between B and C will be:
1. 4 A
2. 2 A
3. 1 A
4. 3 A
A network of resistors is connected to a 16 V battery with an internal resistance of 1 Ω, as shown in the figure. The voltage drop across AB is:
1. 2 V
2. 25 V
3. 4 V
4. 6 V
A battery of 10 V and negligible internal resistance is connected across the diagonally opposite corners of a cubical network consisting of 12 resistors each of resistance 1 Ω (as shown in the figure). The total current in the network is:
1. 6 A
2. 12 A
3. 4 A
4. 2 A
The current in the branch AB in the given network is:
1. 5/8 A
2. 5/2 A
3. 15/8 A
4. 3/2 A
The four arms of a Wheatstone bridge have the following resistances as shown in the figure. A galvanometer of 15Ω resistance is connected across BD. What is the current through the galvanometer when a potential difference of 10 V is maintained across AC?
1. 4.87 mA
2. 3.72 mA
3. 5.01 mA
4. 2.65 mA
In a meter bridge (shown in the figure), the null point is found at a distance of 33.7 cm from A. If now a resistance of 12 Ω is connected in parallel with S, the null point occurs at 51.9 cm. The values of R and S are respectively:
1. 13.5 Ω, 6.86 Ω
2. 13.5 Ω, 13.5 Ω
3. 6.86 Ω, 6.86 Ω
4. 6.86 Ω, 13.5 Ω