1
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 60 English
A
$$\left( {{{2r} \over {\sqrt 3 }}} \right)$$
B
$$\left( {{{2r} \over 3}} \right)$$
C
$${\left( {{1 \over {\sqrt 2 }}} \right)^2}$$
D
$$\left( {{r \over {\root 3 \of 2 }}} \right)$$
2
NEET 2013
MCQ (Single Correct Answer)
+4
-1
Change Language
In Young's double slit experiment, the slits are 2 mm apart and are illuminated by photons of two wavelengths $${\lambda _1}$$ = 12000 $$\mathop A\limits^ \circ $$ and $${\lambda _2}$$ = 10000 $$\mathop A\limits^ \circ $$. At what minimum distance from the common central bright fringe on the screen 2 m from the slit will a bright fringe from one interference pattern coincide with a bright fringe from the other ?
A
4 mm
B
3 m
C
8 mm
D
6 mm
3
NEET 2013
MCQ (Single Correct Answer)
+4
-1
Change Language
A parallel beam of fast moving electrons is incident normally on a narrow slit. A fluorescent screen is placed at a large distance from the slit. If the speed of the electrons is increased, which of the following statements is correct ?
A
The angular width of the central maximum will decrease.
B
The angular wifth of the central maximum will be unaffected.
C
Diffraction pattern is not observed on the screen in the case of electrons.
D
The angular width of the central maximum of the diffraction pattern will increase.
4
NEET 2013
MCQ (Single Correct Answer)
+4
-1
Change Language
For photoelectric emission from certain metal the cutoff frequency is $$\upsilon $$. If radiation of frequency 2$$\upsilon $$ impinges on the metal plate, the maximum possible velocity of the emitted electron will be (m is the electron mass)
A
$$\sqrt {{{2h\upsilon } \over m}} $$
B
$$2\sqrt {{{h\upsilon } \over m}} $$
C
$$\sqrt {{{h\upsilon } \over {\left( {2m} \right)}}} $$
D
$$\sqrt {{{h\upsilon } \over m}} $$
EXAM MAP
Medical
NEETAIIMS
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
Civil Services
UPSC Civil Service
Defence
NDA
Staff Selection Commission
SSC CGL Tier I
CBSE
Class 12