The temperature coefficient of resistance of a wire is 0.00125 peroC. At 300 k, its resistance is I ohm. This resistance of the wire will be 2 ohm at.
1154oK
1100oK
1400oK
1127oK
A constant voltage is applied between the two ends of a uniform metallic wire. Some heat is developed in it. The heat developed is doubled if
Both the length and the radius of the wire are halved.
Both the length and the radius of the wire are doubled
The radius of the wire is doubled
The length of the wire is doubled
A 4 (F capacitor, a resistance of 2.5 M( is in series with 12 V battery. Find the time after which the potential difference across the capacitor is 3 times the potential difference across the resistor. [Given In (2)= 0.693]
13.86s
6.93s
7s
1.4s
Unit of specific resistance is ____.
ohm
ohm-s
ohm-metre
ohm per metre
Which switch in the circuit when closed will produce short-circuiting?
A
B
C
None of the above
Unit of conductance can’t be expressed in ____.
mho
(ohm)-1
siemen
ohm m-1
In comparing e.m.f two cells with the help of a potentiometer, at the balance point, the current flowing through the wire is taken from ____.
one of these cells
both of these cells
the battery in the circuit
none of these
A battery of 20 cells (each having e.m.f. 1.8 volt and internal resistance 0.1 ohm) is charged by 220 volts and the charging current is 15A. The resistance to be put in the circuit is ____.
10.27 ohms
12.27 ohms
8.62 ohms
16.24 ohms
If a resistance 5 is connected in the left gap of a meter bridge and 15 in the other gap then position of balancing point is
10 cm
20 cm
25 cm
75 cm
A potentiometer wire, 10 m long has resistance 40 ohms. If it is put in series to a resistance 760 ohms and connected to a 2 volts battery, then potential gradient in the wire is ____.
1 x 10-2 volt/m
1 x 10-3 volt/m
1 x 10-4 volt/m
1 x 10-5 volt/m