Question

_______ 7) Six moles of a diatomic gas at a temperature of 330 OC occupy a volume of 750 cm3,

           what pressure does this gas exert?

      (a) 2.2 x 103 N/m2       (b) 4 x 103 N/m2      (c) 2.2 x 107 N/m2          (d) 6.7 x 106 N/m2        

      (e) 4 x 107 N/m2

_______ 8) Which of the statements below is NEVER true?

(a) If an object is placed outside the focal point of a concave (diverging) lens, it will form an inverted image.

(b) If an image produced by a thin lens is real, it is inverted.

(c) If a thin lens produces a magnified image, the lens has a positive focal length.

(d) If a ray is refracted toward the normal, it entered a more optically dense medium.

Answer 1

7) Let the pressure the gas exert is P.

The temperature of the gas T=330oC=(330+273) K=603 K.

Number of moles of the gas is n=6 moles.

We know from the gas formula

  

  

  

8)

The answer is (a)  If an object is placed outside the focal point of a concave (diverging) lens, it will form an inverted image.

Note : A concave lens always makes virtual image and virtual image always an errect image not inverted.

Note: Only a convex lens can makes magnified image and concave lens has positive focal length.

Note: If a ray enters from a rare medium to denser medium then the ray refracted twoards the normal.