A boiling pot of water (the water travels in a current throughout the pot), a hot air balloon (hot air rises, making the balloon rise) , and cup of a steaming, hot liquid (hot air rises, creating steam) are all situations where convection occurs.
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Answer:1). Distance of far point x=0.9m
Therefore, since the image is virtual
-f=-x = -0.9m
Power of the concave lenses = 1/f = 1/-0.9
= -1.11D
2 ) near point is 21cm = 0.21m
Power = 4-1/near point
= 4/0.21
= 14.2D.
Answer:
Option B is the correct answer.
Explanation:
Velocity of a body = Displacement of the body/Time taken
Displacement and velocity are a vector. Both have direction and magnitude.
Displacement is generally distance with direction.
If we divide distance with time taken we will get speed of the airplane. Speed with direction is called velocity. So we need distance between Houston and Dallas, time taken by plane to travel from Houston to Dallas and direction of displacement from Houston to Dallas.
So we need direction.
Option B is the correct answer.