intensity of a star is inversely depends on the square of the distance from the star
we can say it is given as

here we know that

also we know that

now we will have



so other star is at distance 60 Light years
Answer:
No concave lens cannot be used to make hand lens because in hand Lens we use convex lens so as to converge the rays of the light After refraction and helps to produce a magnified image of an object.
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Answer:
Explanation:
Block A sits on block B and force is applied on block A . Block A will experience two forces 1) force P and 2 ) friction force in opposite direction of motion . Block B will experience one force that is force of friction in the direction of motion .
Let force on block A be P . friction force on it will be equal to kinetic friction, that is μ mg , where μ is coefficient of friction and m is mass of block A
friction force = .4 x 2.5 x 9.8
= 9.8 N
net force on block A = P - 9.8
acceleration = ( P - 9.8 ) / 2.5
force on block B = 9.8
acceleration = force / mass
= 9.8 / 6
for common acceleration
( P - 9.8 ) / 2.5 = 9.8 / 6
( P - 9.8 ) / 2.5 = 1.63333
P = 13.88 N .
Using the idea of work done under gravity, the height of the building is 187 m.
<h3>Work done in a gravitational field</h3>
We must recall that the work done in a gravitational field is given by; mgh
m= mass
g = acceleration due to gravity
h = height
mass = 60.0 kg
Workdone = 1.15x10^5 J
W = mgh
h = W/mg
h = 1.15x10^5 J/60.0 kg * 9.8 ms-2
h = 187 m
Learn more about work done: brainly.com/question/13662169?
If the two waves have the SAME FREQUENCY and are exactly
out of phase (180° apart), then the resultant wave will have the
same frequency and an amplitude of 1 unit.
If the two waves do not have the SAME FREQUENCY, then their
relative phase is meaningless.