CBSE physics
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When electrons drift in a metal from lower to higher potential, does it mean that all the free electrons of the metal are moving in the same direction?
No. When electric field is applied, the net drift of the electrons is from lower to higher potential. But, locally electrons collide with ions and may change its direction during the course of their motion.
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The horizontal component of the earth’s magnetic field at a place is B and angle of dip is 60°.
What is the value of vertical component of earth’s magnetic field at equator?
Vertical component of magnetic field at the equator is zero. At the equator, the direction of magnetic field is horizontal.
Show on a graph, the variation of resistivity with temperature for a typical semiconductor.
For a semiconductor, resistivity decreases rapidly with increase in temperature.
Why should electrostatic field be zero inside a conductor?
In a conductor, charge resides on the surface. So, charge inside the conductor is zero.
Then, according to the Gauss Theorem, electrostatic field is zero. 
Name the physical quantity which remains same for microwaves of wavelength 1 mm and UV radiations of 1600 Å in vacuum.
Both microwaves and UV radiations are EM waves. Therefore, their speed ( c = 
) will remain same in vacuum.
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Mock Test Series
Mock Test Series