Answer:

Explanation:
We have,
The surface temperature of the star is 60,000 K
It is required to find the wavelength of a star that radiated greatest amount of energy. Wein's displacement law gives the relation between wavelength and temperature such that :

Here,
= wavelength

So, the wavelength of the star is
.
Answer:
change in momentum, 
Average Force, 
Explanation:
Given:
angle of kicking from the horizon, 
velocity of the ball after being kicked, 
mass of the ball, 
time of application of force, 
We know, since body is starting from the rest
.....................(1)


Now the components:


similarly


also, impulse
.........................(2)
where F is the force applied for t time.
Then from eq. (1) & (2)



Now, the components


&


Answer:
nitrogen
Explanation:
because I also had this in exam and I was correct
Answer:
u = - 20 cm
m =
Given:
Radius of curvature, R = 10 cm
image distance, v = 4 cm
Solution:
Focal length of the convex mirror, f:
f = 
Using Lens' maker formula:

Substitute the given values in the above formula:


u = - 20 cm
where
u = object distance
Now, magnification is the ratio of image distance to the object distance:
magnification, m =
magnification, m =
m =
m =
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