A current of 5 amperes is passing through a metallic wire of cross-section area 4 x 10-6 m2. If the density of the charge carrier in the wire is 5 x 1026/m3, the drift velocity of the electrons is ____.
1/8 m/s
1/16 m/s
1/64 m/s
1/78 m/s
What constitutes current in a metal wire?
electrons
protons
atoms
molecules
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
Kirchhoff’s second law is based on the law of conservation of ____.
charge
energy
momentum
sum of mass and energy
If three 2 ohms resistance are connected to from a triangle, then equivalent resistance between any two corners is ____.
6 ohms
2 ohms
¾ ohms
4/3 ohms
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
The thermocouple is based on the principle of :
Seebeck effect
Thomson effect
Peltier effect
Joule effect
Thermocouple is a device for the measurement of :
Absolute temperature of a metal
The temperature difference between two substances
The couple acting on a wire
Thermal conductivity of a substance
The true statement for thermo e.m.f. of a thermocouple :
Depends on the nature of metals
Depends only on temperature of cold junction
Depends only on temperature of hot junction
Depends on the length of the wires used for thermocouple
The direction of current in an iron-copper thermocouple is :
From copper to iron at the hot junction
From iron to copper at the hot junction
From copper to iron at cold junction
No current will flow