Read the following statements carefully:
Y : The resistively of a semiconductor decreases with increases of temperature.
Z: In a conducing solid, the rate of collisions between free electrons and ions increases with increases of temperature
Select the correct statement (s) from the following:
Y is true but Z is false
Y is false but Z is true
Both Y and Z are true
Is true and Z is the
Electric intensity at a point varies as r-3 for ____.
a point charge
an electric dipole
a plane infinite sheet of charge
a line charge of infinite length
If a pellet carrying a charge of 0.5 coulomb is accelerated through a potential of 2000 volts, then it attains a kinetic energy equal to ____.
1000 joule
1000 ergs
1000 kilowatt-hours
500 ergs
There is no flow of current between two charged bodies when connected because, they have the same ____.
quantity of charge
potential
capacity
ratio of potential per unit charge
If a unit charge is taken from one point to another over an equipotential surface, then ____.
work is done on the charge
work is done by the charge
work done on the charge is constant
no work is done
Materials which allow larger currents to flow through them are ____.
Insulators
semi-conductors
conductors
alloys
If 1 is the current through a wire and e is the charge of electron, then number of electrons in t seconds will be ____.
1e/t
1te
e/1t
1t/e
Conventionally, the direction of the current is taken as the direction of flow ____.
to negative charge
the direction of flow of atoms
of molecules
of positive charge
Ratio of the electrostatic to gravitational force between two electrons placed at a certain distance in air will be ____.
4.2 x1042
4.2 x 10-42
2.4 x 1024
2.4 x 10-24
If length of a wire is doubled and its cross-section is also doubled, then the resistance wills ____.
increases eight times
decreases four times
become four times
remain unchanged