Question

consider the apparatus shown in the figure to the right in which a conducting bar can be moved along two rails connect

0,206N X X X Consider the apparatus shown in the fig- ure to the right in which a conducting bar can be moved along two rails connected to a lightbulb. The whole system is im- mersed in a magnetic field fof magnitude B = 0.400 T perpendicular and into the page. The distance between the horizon- tal rails is l = 0.800 m. Th resistance of the lightbulb, R = 48.0 2, is assumed to be constant. The bar and rails have negli- gible resistance. The bar is moved toward the right by a constant force of magnitude F = 0.600 N. We wish to find the maxi- mum power delivered to the lightbulb. (a) Find an expression for the current in the lightbulb as a function of magnetic field (B), current (1), resistance (R), and speed of the bar (v). (b) Find the numerical value for the speed of the bar when the maximum power is being delivered to the lightbulb. (c) Find the current in the lightbulb when maximum power is being delivered. (d) Using P = 1?R, what is the maximum power delivered to the lightbulb? (e) What is the maximum mechanical input power delivered to the bar by the force F? (f) We have assumed the resistance of the lightbulb is constant. In reality, as the power delivered to the lightbulb increases, the filament temperature increases and the resistance increases. Does the speed found in part (b.) change is the resistance increases and all other quantities are held constant?

Answer 1

Pant-(e) Pant fb) emf induced along rod e= Bul Current Is e I = Bull ve In that case Fragnetic f BId = F B (Bul d = F = = FR 0.60x48 (0.42x (06) 2 => V=281.25 mls Current I = Bul - 04x281.25 x 0.60 48 I=1.875 A B212 Pant-(c) Part- (d) P= I2R - IP=168.75 Welt Panta (f) mehanics power P=FV = 0.600 X 281.25 P = 168.75) West If Rincreases, V&R speed of bar also increases speed will increase Power also increases Power will be larger. Pont (b) part (i)