Answer:
d. It increases numerical aperture and maintains a uniform light speed.
Explanation:
In optical microscopes, various immersion mediums are used to improve or enhance the resolution. Immersion oils like cedar and Leica oils are one of those mediums which are used to improve resolution by increasing the numerical aperture and keeping the speed of light uniform.
<span>If an inductor is connected across an ac source and suppose the frequency of the source is doubled, then t</span>he inductive reactance of the inductor is also doubled. The inductive reactance (XL) is the t<span>he opposition to current flowing through a coil in an AC circuit, the </span>impedance measured in Ohms and can be calculated with the following formula:
XL=2*pi*f*L,
where f is the frequency. So, if the frequency is doubled than also the inductive reactance is doubled.
One charge is enough in order to have an electric field.
In fact, every charge generates an electric field: for example, the electric field generated by a single point positive charge is radial, as shown in the attached figure. More complicate electric field configurations can be obtained adding charges or using more complicate charge distributions, but one charge is enough to have an electric field.
Answer: C) velocity is a vector and requires a direction.
Explanation:
In physics, there are two types of quantities:
- scalars: these are quantities that have only a magnitude
- vectors: there are quantities that have both magnitude and direction
As an example, speed is a scalar while velocity is a vector. Therefore, speed has only a magnitude, while velocity has both magnitude and direction: therefore, the difference between the two quantities is that velocity is a vector and requires a direction, as stated in option C.
The answer is Light rays are reflected by mirrors