The weight of a body is the same, no matter where the body is ...

[Yi-Chen]

The weight of a body is the same, no matter where the body is located.
 
  What will be an ideal response?

Question 2

Are solar cell efficiencies of over 30 realizable under realistic use conditions (include cost in these conditions)? Explain.
 
  What will be an ideal response?

[stallen]

Answer to Question 1

Not so. A body's mass is the same regardless of location, but the weight of a
body depends on its location.

Answer to Question 2

This is difficult to give a definitive answer to. In the past, the efficiencies at the
frontiers of research were higher and very expensive. As the frontier advanced, these
efficiencies were available for much more modest costs. At present, 30 efficiency solar
cells are quite expensive. If the trends of the efficiencies and costs up to the present
continues to hold, these solar cells will be much cheaper in the coming decades.

[Yi-Chen]

Thank you!

[stallen]

Always glad to help...