1) In the formation of a star a large volume of gas and dust particles contracts due to gravitational pull. Which of the following is/are true of this contracting mass of gas?
(i) the pressure and temperature inside the mass increase.
(ii) the temperature inside the mass increases, but pressure decreases.
(iii) the gas particles slow down as a result of the decrease in volume.
(iv) the gas particles speed up and they hit against each other more violently?
A) (i) and (iv) only
B) (i), (ii) and (iv) only
C) (i) only
2) Which of the following optical instruments uses plane mirrors?
A) periscope
B) magnifying glass
C) microscope
D) telescope
3) The capacitance of a parallel plate capacitor can be increased by?:
A) increasing its electrical potential
B) increasing the distance between the plates
C) increasing its surface area
D) increasing the charge on it