1
NEET 2013
MCQ (Single Correct Answer)
+4
-1
Change Language
A plano convex lens fits exactly into a plano concave lens. Their plane surfaces are parallel to each other. If lenses are made of different materials of refractive indices $$\mu $$1 and $$\mu $$2 and R is the radius of curvature of the curved surface of the lenses, then the focal length of the combination is
A
$${R \over {\left( {{\mu _1} - {\mu _2}} \right)}}$$
B
$${{2R} \over {\left( {{\mu _2} - {\mu _1}} \right)}}$$
C
$${R \over {2\left( {{\mu _1} + {\mu _2}} \right)}}$$
D
$${R \over {2\left( {{\mu _1} - {\mu _2}} \right)}}$$
2
NEET 2013
MCQ (Single Correct Answer)
+4
-1
Change Language
Two pith balls carrying equal charges are suspended from a common point by strings of equal length, the equilibrium separation between them is r. Now the strings are rigidly clamped at half the height. The equilibrium separation between the balls now become

NEET 2013 Physics - Electrostatics Question 63 English
A
$$\left( {{{2r} \over {\sqrt 3 }}} \right)$$
B
$$\left( {{{2r} \over 3}} \right)$$
C
$${\left( {{1 \over {\sqrt 2 }}} \right)^2}$$
D
$$\left( {{r \over {\root 3 \of 2 }}} \right)$$
3
NEET 2013
MCQ (Single Correct Answer)
+4
-1
Change Language
When a proton is released from rest in a room, it starts with an initial acceleration $$a$$0 towards west. When it is projected towards north with a speed $$v$$0 it moves with an initial acceleration 3$$a$$0 towards west. The an initial accelearation 3a0 towards west. The an initial acceleration 3$$a$$0 toward west. The electric and magnetic fields in the room are
A
$${{m{a_0}} \over e}$$ east,  $${{3m{a_0}} \over {e{v_0}}}$$ up
B
$${{m{a_0}} \over e}$$ east,  $${{3m{a_0}} \over {e{v_0}}}$$ down
C
$${{m{a_0}} \over e}$$ west,  $${{2m{a_0}} \over {e{v_0}}}$$ up
D
$${{m{a_0}} \over e}$$ west,  $${{2m{a_0}} \over {e{v_0}}}$$ down
4
NEET 2013
MCQ (Single Correct Answer)
+4
-1
Change Language
A current loop in a magnetic field
A
can be in equilibrium in two orientations, both the equilibrium states are unstable.
B
can be in equilibrium in two orientations, one stable while the other is unstable.
C
experiences a torque whether the field is uniform or non uniform in all orientations.
D
can be in equilibrium in one orientation.