[填空题]
An ordinary flashlight uses two6tjh e,a1 v (mq(y.g6bnac4kk D-cell 1.5-V 9qn behwo/ nbb dy4:e3ac .+)ybatteries connected in series as in Fig. 18–4b (Fig. 18–dc+. y 9o3b4n qw)ea:/nbyehb 36). The bulb draws 450 mA when turned on.
(a) Calculate the resistance of the bulb and the power dissipated.
$\approx$ $\Omega$(retain one decimal places)
W
(b) By what factor would the power increase if four D-cells in series were used with the same bulb? (Neglect heating effects of the filament.) Why shouldn’t you try this?
