- AIsaac Newton
- BChristian Huygens
- CThomas Young
- DAugustin Jean Fresnel
Explanation:
In 1678, Dutch physicist, Christian Huygens, believed that the light was made up of waves vibrating up and down perpendicular to the direction of the light travels and therefore formulated away of visualising wave propagation.
This becomes know as Huygens principle. Huygens theory was the successful theory of light in three dimensions. Huygens suggested that the light wave peaks form from surfaces like the layers of onion. In a vacuum or other uniform mediums the light waves are spherical and these wave surfaces advance or spread out as they travel at the speed if light.
This theory explains why light shining through a pinhole or slitwall spread out rather than going in straight lines.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
If a piece of metal was thought to be magnet, which one of the following observations would offer conclusive evidence
|
(a) It attracts a known magnet |
(b) It repels a known magnet |
|
(c) Neither (a) nor (b) |
(d) It attracts a steel screw driver |
The activity of a sample is 64 × 10–5 Ci. Its half-life is 3 days. The activity will become 5 × 10–6 Ci after
|
(a) 12 days |
(b) 7 days |
(c) 18 days |
(d) 21 days |
If the dielectric constant and dielectric strength be denoted by k and x respectively, then a material suitable for use as a dielectric in a capacitor must have
|
(a) High k and high x |
(b) High k and low x |
(c) Low k and low x |
(d) Low k and high x |
The tail of the comet is due to
|
(a) Vaporisation of water on the comet |
|
(b) Sublimation of vapour in the comet |
|
(c) Cooling of water in the comet |
|
(d) Vaporisation of heat in the comet |
Two sources of equal emf are connected to an external resistance R. The internal resistances of the two sources are and
. If the potential difference across the source having internal resistance
is zero, then
|
(a) |
(b) |
|
(c) |
(d) |
Circular part in the centre of retina is called
|
(a) Blind spot |
(b) Yellow spot |
(c) Red spot |
(d) None of the above |
In the circuit shown here and battery B = 20V. The switch
is first closed. It is then opened and afterwards
is closed. What is the charge finally on
|
(a) 120 μC |
(b) 80 μC |
(c) 40 μC |
(d) 20 μC |