Answer: C
Explanation: When light rays moves from one medium to another with a change in its direction (bending towards media interface), it is called refraction.
The angle the ray in the second medium (refracted ray) makes with the medium interface (normal) explains the bending of light and is dependent on the following the refractive index (n), wave speed in the medium (v) and other properties such as wavelength, and angle of incidence.
This question is focused on the relationship between refractive index and wave speed.
Refractive index (n) is inversely proportional to wave speed (v). This implies that a ray of light moving from a dense medium (say air) to a more dense medium (say glass) has it wave speed decreased and if reversed ( from glass to air) the wave speed increases.
A change in refractive index also affects the bending of the refracted ray.
A move from a dense to a more dense medium makes the refracted ray move towards the normal thus decreasing the angle of refraction (angle the refracted ray makes with the normal)
So for our question, since light ray (refracted ray) moves towards the glass to glass interface (normal) it means that light ray had moved from a dense to a more dense medium (that is glass 2 has higher refractive index than glass one) and the wave speed will decrease since there is an increase in refractive index (that is light travels faster in glass 1 than glass 2)
Answer : (A) A charged object is brought near a neutral object without touching it.
Explanation:
Bodies can be charged by the method of conduction. By conduction the body acquires the same charge as on the charging body.
Charging the body can be understood by the following example of charging a paper cylinder by conduction. Make a paper cylinder by rolling a strip of paper on a pencil and then gently pulling out the pencil. Suspend the paper cylinder by a string tied to its center, now touch the paper cylinder with a glass rod rubbed with silk so it has a positive charge. Remove the class rod and the again bring it near to the paper cylinder.
The paper cylinder is repelled by the positively charged rod. And when you bring a negatively rubbed rod, next to the cylinder it will be attracted towards the rod. This means that the paper cylinder has acquired a positive charge as on the glass rod due to conduction.
The unit for measuring the rate at which light is radiated from a source is B, Lumen. Lumenous flux is the time rate of the flow of light, or the visible energy produced from a certain light source. It is the quantitative measure of brilliance of a light source. The unit we use for this is lumen.
Fission. In a nuclear explosion the atom nucleus splits, not in a conventional explosion
<span>If the balloon is closed then both volume and pressure will increase when the gas inside is heated.</span>
