A 10 metre potentionmeter wire has a resistance of 20 Ω. It is connected in series with a battery of emf 2.5 volt and a resistance of 5 Ω. The potential gradient along wire in volt cm-1 is
0.002
0.02
0.2
0.0025
Kirchhoff's current law at a junction deals with conservation of
charge
energy
momentum
all of these
An electirc kettle boils 1 kg of water in time t1 and another kettle boils the same amount of water in time t2. When they are joined in series, the time required to boil 1 kg of water is
t1 + t2
The resistance of hot tungsten filament is about 10 times the cold resistance. What will be the resistance of 100 W and 200 V lamp when not in use?
20 Ω
40 Ω
200Ω
400Ω
In a potentiometer of 10 wires,the balance point is obtained on the 7th wire.To shift the balance point to 9th wire,we should
decrease resistance in the main circuit
increase resistance in the main circuit
decrease resistance in series with the cell whose emf is to be measured
increase resistance in series with the cell whose emf is to be determined
The resistance of a discharge tube is
zero
ohmic
non - ohmic
infinity
A 6 V battery is connected to the terminals of a three metre long wire of uniform thickness and resistance of . The difference of potential between two points on the wire separated by a distance of 50cm will be
2 V
3 V
1 V
1.5 V
A 2 kW boiler used for 1 hour everyday consumes electrical energy in thirty days equal to
120 units
60 units
15 units
30 units
A storage battery is connected to the mains for charging with emf of 12.5 V. The internal resistance of the storage battery is 1 Ω. When the charging current is 0.5 A, the potential difference across the storage battery is
13 V
12.5 V
12 V
11.5 V
In a potentiometer of 10 wires, the balance point is obtained on the 7th wire. To shift the balance point to 9th wire, we should
increase resistance in series with circuit
increase resistance in series with the cell whose emf is to be determine
