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Question Bank No: 2

1. Fuse wire is a wire of

a)		low resistance
b)		high resistance and high melting point
c)		low resistance and high melting point
d)		high resistance and low melting point

2. In an electrolyte solution electric conduction is due to the flow of

a)		electrons
b)		protons
c)		positive ions only
d)		negative and positive ions

3. The thermo emf developed in a thermo couple depends

a)		only on the temperature of the cold junction
b)		only on the temperature of the hot junction
c)		only on the temperature difference between the junctions
d)		only on the temperature difference between the junctions and nature of the metals

4. Thermo emf of a couple is maximum when its hot junction is at

a)		temperature of invention
b)		$100^{0} C$ if the cold junction is at $10^{0} C$
c)		$543^{0} C$ when the cold junction is at $0^{0} C$
d)		neutral temperature

5. In Seeback series Sb appears before Bi, therefore, in Sb-Bi thermocouple current flows from

a)		Sb to Bi through hot junction
b)		Sb to Bi through cold junction
c)		Bi to Sb through cold junction
d)		can flow in both direction

6. For the thermocouple, the thermo emf may be

a)		positive
b)		negative
c)		zero
d)		positive, negative or zero

7. The emf in thermo electric circuit with one junction at $0^{0} C$ and the other at $t^{0} C$ is given by $E = a t + b t^{2} .$ The neutral temperature is

a)		a/b
b)		b/a
c)		-a/b
d)		2b/a

8. The net charge on current carrying conductor is

a)		positive
b)		negative
c)		varying
d)		zero

9. Two copper wires A and B of same diameter have lengths 3cm and 5cm respectively. Ra and Rb are the resistances of A and B and $ρ$ a and $ρ$ b are the resistivities respectively. Identify the correct statement from the following

a)		Ra > Rb, $ρ$ a > $ρ$ b
b)		Rb > Ra, $ρ$ a > $ρ$ b
c)		Ra > Rb, $ρ$ a < $ρ$ b
d)		Ra < Rb, $ρ$ a = $ρ$ b

10. 'n' cells each of emf 'E' and internal resistance 'r' send the same current through an external resistance R whether the cells are connected in the series or in parallel. Then

a)		R = nr
b)		R = r
c)		r = nR
d)		R = r $\sqrt{n}$

11. A primary cell has an emf of 1.5E .When short circuited it gives a current of 3A. The internal rsistance of the cell is

a)		4.5 ohm
b)		2 ohm
c)		0.5 ohm
d)		$\frac{1}{4.5}$ ohm