Answer: Light could be thought of as a stream of tiny particles discharged by luminous objects that travel in straight paths.
Explanation:
We can define "radiation" as the transmision of energy trough waves or particles.
Particularly, light is a form of electromagnetic radiation, so the "tiny particles" of light are discharged by a radiating object, particularly we can be more explicit and call it a luminous object, in this way we are being specific about the nature of the radiation of the object.
Given data:
* The extension of the steel wire is 0.3 mm.
* The length of the wire is 4 m.
* The area of cross section of wire is,
* The young modulus of the steel is,
Solution:
The young modulus of the steel in terms of the force and extension is,
where F is the force acting on the steel wire,, l is the original length of the wire, dl is the extension of the wire, and A is the area,
Substituting the known values,
Thus, the force which produce the extension of 0.3 mm of the steel wire is 31.5 N.
Answer:
16.2 s
Explanation:
Given:
Δx = 525 m
v₀ = 0 m/s
a = 4.00 m/s²
Find: t
Δx = v₀ t + ½ at²
525 m = (0 m/s) t + ½ (4.00 m/s²) t²
t = 16.2 s
B- at night
In eyes of the humans, and many other animals there are two types of receptors, the rods, and the cones. The cones have an important role in color vision and they possess different types of pigment which enable color vision.
On the other hand, the rods are more sensitive to light, and they are responsible for black and white vision.
Therefore, an increase in the number of rods can enable the animal to see betther in the dark.
