For which optical devices does d¡ always have a negative value? A. A and B
B. A and D
C. Band D
D. B and C

When you push downward on a book at rest on a table, you feel an upward force. does this force depend on friction? defend your answer.

The charge on a charged sphere is: a)concentrated at its centerb)distributed uniformly throughout its volumec)clustered on its centerd)distributed uniformly over its surface

5g of ammonium nitrate was dissolved in 60g of water in an insulated container. the temperature at the start of the reaction was 23.0°c and at the end it was 19.0°c. calculate the energy absorbed by the reaction.