<span>The answer is letter C.
Reflecting telescopes are more powerful than refracting telescopes. These are also called as reflectors which serves an optical telescope that uses a single or combination of curved mirrors. These mirrors then reflect light and form an image. It is designed for very large diameter objects and are mostly considered as major telescopes in the field of astronomy. They were used as an alternative for refracting telescopes during the 17th century because they suffer less chromatic aberrations than a refracting telescope does. <span>
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Answer b protons and electrons
Answer:
a) 
b) 
c) 
Explanation:
the gravitational potential energy is given by:
The kinetic energy is given by:
the initial kinetic energy is zero because the motion started from rest, so:
applying the conservation of energy theorem:
The work done by the friction force is given by:
the angle of the force is 180 degrees because it's against the movement:
Answer:
Explanation:
For calculating resistance of a conductor , the formula is
R = ρ l / A , ρ is specific resistance , l is length and A is cross sectional area of wire.
For first wire length is l₁ , area is A₁ resistance is R₁, for second resistance is R₂ , length is l₂ and area is A₂
Given , l₁ = 2l₂ , A₁ = 4A₂ , area is proportional to square of thickness.
R₁ / R₂ = I₁A₂ / I₂A₁
= 2l₂ x A₁ / 4 I₂A₁
= 1 / 2
2R₁ = R₂
Power = V² / R
Ratio of power = (V² / R₁) x (R₂ / V²)
= R₂ / R₁
= 2 .
