Flow of electrons through a copper wire
Answer:
d. 50 C
Explanation:
In this problem, we have to add 800 ml of water at 20 Celsius to 800 ml of water at 80 Celsius.
According to the 2nd law of thermodynamics, heat transfers from hot to cold temperature.
The quantity of both the different waters is equal so this makes it very easy. All we have to do is find the mean of both the temperatures:
Final temperature = (20 C + 80 C)/2
= 50 Celsius
m=23.8kg a=8.97m/s^2 Fnet=? Fnet=ma=(23.8kg)(8.97m/s^2)=213.486N
It is given that for the convex lens,
Case 1.
u=−40cm
f=+15cm
Using lens formula
v
1
−
u
1
=
f
1
v
1
−
40
1
=
15
1
v
1
=
15
1
−
40
1
v=+24.3cm
The image in formed in this case at a distance of 24.3cm in left of lens.
Case 2.
A point source is placed in between the lens and the mirror at a distance of 40 cm from the lens i.e. the source is placed at the focus of mirror, then the rays after reflection becomes parallel for the lens such that
u=∞
f=15cm
Now, using mirror’s formula
v
1
+
u
1
=
f
1
v
1
+
∞
1
=
15
1
v=+15cm
The image is formed at a distance of 15cm in left of mirror
Answer:
v = 2,99913 10⁸ m / s
Explanation:
The velocity of propagation of a wave is
v = λ f
in the case of an electromagnetic wave in a vacuum the speed that speed of light
v = c
When the wave reaches a material medium, it is transmitted through a resonant type process, whereby the molecules of the medium vibrate at the same frequency as the wave, as the speed of the wave decreases the only way that they remain the relationship is that the donut length changes in the material medium
λ = λ₀ / n
where n is the index of refraction of the material medium.
Therefore the expression is
v =
Let's look for the frequency of blue light in a vacuum
f =
f =
f = 6.667 10¹⁴ Hz
the refractive index of air is tabulated
n = 1,00029
let's calculate
v =
450 10-9 / 1,00029 6,667 1014
v = 2,99913 10⁸ m / s
we can see that the decrease in speed is very small