IIT JEE Advanced & Mains Physics 2018 : Electricity : Rank file / expected questions / Physicsmynd Elite Series / Page IV
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28 ] A spherically symmetrical charge distribution has density
Then the energy stored in region r < R is –
29 ] Two point charges of equal masses and charges m and Q respectively are suspended at a common point by two threads of negligible mass and length l .If at equilibrium, the angle of inclination of each thread to the vertical is , then is proportional to –
30 ] In the above arrangement , if is very small , then is given by –
31 ] Consider two conducting planes kept at a particular angle to each other in the xy axis with the point of contact being at the origin . Obviously . work must be done to bring a point charge to the region of contact between the planes. Then , finding the work done ,using the method of images [in the above case ] is possible if the angle is [ in degrees] –
A ] 20
B ] 30
C ] 40
D ] 50
32 ] The issue with the angle in the above case is due to the fact that there is –
A ] Difficulty in finding the location of the image charge.
B ] Difficulty in finding the location of the equipotential.
C ] Difficulty in finding the location of the charge at infinity .
D ] A and B
E ] A , B and C
33 ] A charge q is kept in a pyramid ,on the center of it’s base ,which is square shaped . Then the flux through any face of the pyramid is –
A ] zero
34 ] A hollow cylinder of resistivity has length L .It’s inner radius is a and outer radius b . Then the resistance produced when a potential difference is generated between the ends of the cylinder is –
35 ] In the above case –
A ] No current flows through the cylinder .
B ] Current flows parallel to the axis of the cylinder.
C ] Current flows radially outward from the axis of the cylinder
D ] Current flows perpendicular to the axis of the cylinder
36 ] Continuing with question no .34 , what if the potential difference is applied between the inner and outer surfaces of the cylinder ? [ Choose the right combination ]
a ) Current flows parallel to the axis of the cylinder.
b ) Current flows radially outward from the axis of the cylinder
c ) Resistance remains the same .
d ) Resistance becomes
e ) Resistance becomes
f ) No current flows through the cylinder
Answer : –
A ] c , e
B } b , d
C ] d , f
D ] c , f