College Physics 2e

# Chapter 25

### Problems & Exercises

1.

Top $1.715 m1.715 m$ from floor, bottom $0.825 m0.825 m$ from floor. Height of mirror is $0.890 m0.890 m$, or precisely one-half the height of the person.

5.

$2.25×108 m/s2.25×108 m/s$ in water

$2.04×108 m/s2.04×108 m/s$ in glycerine

7.

$1.4901.490$, polystyrene

9.

$1 . 28 s 1 . 28 s$

11.

$1.03 ns 1.03 ns$

13.

$n=1.46n=1.46$, fused quartz

17.

(a) 0.898

(b) Can’t have $n<1.00n<1.00$ since this would imply a speed greater than $cc$.

(c) Refracted angle is too big relative to the angle of incidence.

19.

(a) $c5.00c5.00$

(b) Speed of light too slow, since index is much greater than that of diamond.

(c) Angle of refraction is unreasonable relative to the angle of incidence.

22.

$66 . 3º 66 . 3º$

24.

$> 1 . 414 > 1 . 414$

26.

1.50, benzene

29.

$46 . 5º , red; 46 . 0º , violet 46 . 5º , red; 46 . 0º , violet$

31.

(a) $0.043º0.043º$

(b) $1.33 m1.33 m$

33.

$71.3º 71.3º$

35.

$53.5º , red; 53.5º , red;$ $55.2º , violet 55.2º , violet$

37.

$5.00 to 12.5 D 5.00 to 12.5 D$

39.

$− 0.222 m − 0.222 m$

41.

(a) 3.43 m

(b) 0.800 by 1.20 m

42.

(a) $−1.35 m−1.35 m$ (on the object side of the lens).

(b) $+10.0+10.0$

(c) 5.00 cm

43.

44.4 cm

45.

(a) 6.60 cm

(b) –0.500

47.

(a) $+7.50 cm+7.50 cm$

(b) $13.3 D13.3 D$

(c) Much greater

49.

(a) +6.67

(b) +20.0

(c) The magnification increases without limit (to infinity) as the object distance increases to the limit of the focal distance.

51.

$− 0 . 933 mm − 0 . 933 mm$

53.

+0.667 m

55.

(a) $–1.5×10–2m–1.5×10–2m$

(b)$–66.7 D–66.7 D$

57.

+0.360 m (concave)

59.

(a) +0.111

(b) -0.334 cm (behind “mirror”)

(c) 0.752cm

61.
$m = h i h o = − d i d o = − − d o d o = d o d o = 1 ⇒ h i = h o m = h i h o = − d i d o = − − d o d o = d o d o = 1 ⇒ h i = h o$
63.

$6.82 k W/m 2 6.82 k W/m 2$

65.

(a)

(b) No.

(c) No.

(d) Yes. Do you know how you learn best?