In Young’s experiment with one source and two slits, one of the slits is covered with black paper. Then
(A) The fringes will be darker
(B) The fringes will be narrower
(C) The fringes will be broader
(D) No fringes will be obtained and the screen will have uniform illumination
(A) The fringes will be darker
(B) The fringes will be narrower
(C) The fringes will be broader
(D) No fringes will be obtained and the screen will have uniform illumination
(D) No fringes will be obtained and the screen will have uniform illumination
A Young’s double – slit set up for interference is shifted from air to within water. Then the
(A) Fringe pattern disappear
(B) fringe width decreases
(C) fringe width increases
(D) fringe width remains unchanged
In the phenomenon of diffraction of light, when blue light is used in the experiment instead of red light, then
i. Fringes will become narrower
ii. Fringes will become broader
iii. No change in fringe width
iv. None of the above
In the Young’s double slit experiment both the slits are similar. If the length of one of the slits is halved, which of the following is true?
(a) Bright fringes become narrower.
(b) Bright fringes become wider.
(c) Dark fringes become darker
(d) Dark fringes become brighter.
What happen when we use white light in Young’s double slit experiment.
(A) No interference pattern will form
(B) white fringes will form
(C) Central bright fringe will be white
(D) Central fringe will be coloured
In Young’s double slit experiment the distance between the slit and the screen is doubled and the separation between the slit is reduced to half. The fringe width:
(a) is doubled
(b) become four time
(c) is halved
(d) remain unchanged
In Young’s double-slit experiment, the phase difference between the light waves reaching the third bright fringe from the central fringe will be (λ=6000 Å)
(a) zero
(b)2
(c) 4
(d) 6
In Young’s double slit experiment, the central point on the screen is:
(a) bright
(b) dark
(c) first bright and later dark
(d) first dark and later bright
An air capacitor is charged with an amount of charge q and dipped into an oil tank. If the oil is pumped out, the electric field between the plates of capacitor will
(a) increase
(b) decrease
(c) remain the same
(d) becomes zero
In electric arc furnace Cu or Iron is melted due to variation of
(a) current
(b) magnetic field
(c) voltage
(d) electric field
Wave theory of light cannot explain the phenomena of
1. Polarisation 2. Diffraction 3. Interference 4. Crompton effect 5. Photoelectric effect
(A) 3, 4
(C) 1 ,2
(B) 1, 4, 5
(D) 4 ,5
A tiny spherical oil drop carrying a net charge q is balanced in still air with a vertical uniform electric field strength 81/7 x 10⁵ Vm⁻¹. When the field is switched off, the drop is observed to fall with terminal velocity 2 x 10⁻³ ms⁻¹, given g = 9.8 ms⁻², viscosity of the air = 1.8 x 10⁻⁵ Nsm⁻², and the density of oil = 900 kgm⁻¹. The magnitude of q is.
(A) 1.6 x 10⁻¹⁹ C
(B) 3.2 x 10⁻¹⁹ C
(C) 4.0 x 10⁻¹⁹ C
(D) 8.0 x 10⁻¹⁹ C
When a body charges by conduction, its mass
(A) Remains same
(B) Increases
(C)Decreases
(D)Increase or decrease
Two interfering beams have intensities in the ratio of 9:4. Then the ratio of maximum to minimum intensity in the interference pattern is
(A) 25:1
(B) 13:5
(C) 5:1
(D) 3:2
A charge Q is placed at the origin. The electric potential due to this charge at a given point in space is V. The work done by an external force in bringing another charge q from infinity up to the point is
(a) v/q
(b) vq
(c) v+q
(d) v