13)both statements are correct,II is the correct explanation for I
1. Statement-I : The sensitiviry of a moving coil galvanometer is increased by placing a suitable megnetic material as a core in side the will.
Statement-II : Soft iron has ligh megnetic permeability and can not be easily megnetized or demagnetized.
2. Statement-I : If the acceprating potential in a x-ray tube is increased, the cut off wavelength of x-rays coming from coolidge tube does not change.
Statement-II : If the potential difference applied to x-ray tube is increased, the intersity of emitted radia from remains unchanged.
3. Statement-I : In electricity inducter is similar to mass.
Statement-II : Greater the mass, lesser, the ability to be motion. Induetance also delays the charge to reach maximum value.
4. Statement-I : For practical purposes, the earth is used as a refrence at zero potential in electric circuit.
Statement-II : The electrical potential of a shpere of radius R with charge Q uniformly distributed on the
surface is given by Q/ 4piEo
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10 Answers
114)both statements are true,but II is not the correct explanation of I
12. threshold wave length = hc/ eV ' V is accelerating potential
so, statement 1 is wrong
11.statement 2 is false coz soft iron can be magnetized easily
1for 4) if V=Q/4piE0R then arka is right , else wrong statement...........
1pratik,here's my justification:
we all know that field due to sphere at the surface will be Q/4piEoR2.
Also E=-dV/dl
take derivative of field as i suggested(take V=Q/4piEoR
and u will get the value of the field as stated above[1][1][1]
1E=-d(Q/4piE0R)/dR
=-Q/4piE0 (d(1/R)/dR)
=-(Q/4piE0) * (-1/R2)
=Q/4piE0R2
as is expected.
1In electricity Charges i mean q is consider to be equivalent of mass...
Coulumb force F = Kq^2/r^2 --------------> Fg = GM^2/r^2
1the concept of inertia is highlighted here.
mass gives the tendency of matter to remain in the same state of rest or motion.
similarly inductor in a circuit is like inertia in it.
when the current tries to rise,it prevents it from doing so,and when it tries to come down,it opposes it's fall.
this is why inductor is like inertia(mass) in a circuit.