Light Bulbs in a parallel circuit

  • #1
Q: Two bulbs x and y are connected in parallel to a new dry cell. The switch is closed. If bulb x is unscrewed, the brightness of bulb y will
a) double
b) halve
c) remain the same
d) become 0

A: a? The current from the first branch would go into the second branch?
 

Answers and Replies

  • #2
Astronuc
Staff Emeritus
Science Advisor
19,596
2,953
chemistrykid said:
Q: Two bulbs x and y are connected in parallel to a new dry cell. The switch is closed. If bulb x is unscrewed, the brightness of bulb y will
a) double
b) halve
c) remain the same
d) become 0

A: a? The current from the first branch would go into the second branch?
The voltage remains the same. What happens when bulb is removed? Think about the resistance of each bulb, and the relationship between voltage, current and resistance.
 
  • #3
berkeman
Mentor
59,934
10,142
chemistrykid said:
Q: Two bulbs x and y are connected in parallel to a new dry cell. The switch is closed. If bulb x is unscrewed, the brightness of bulb y will
a) double
b) halve
c) remain the same
d) become 0

A: a? The current from the first branch would go into the second branch?
It depends on the battery chemistry. But as with many subtle multiple-choice questions, there is only one best answer in the choices given (as Astro has indicated).

In the real world, however, batteries have a finite output impedance, so even a new battery's output voltage will droop some as it is loaded more. So the output voltage will be a bit less when it is outputting twice the current (to drive both bulbs). So if there were an answer e) that said "increase slightly", that would be the correct choice. Since that isn't listed, what is the next best choice?
 
  • #4
tony873004
Science Advisor
Gold Member
1,752
143
The light bulbs in your home are wired in parallel. If you unscrew one, how does it affect the others?
 

Related Threads on Light Bulbs in a parallel circuit

Replies
2
Views
13K
  • Last Post
Replies
14
Views
25K
  • Last Post
Replies
2
Views
39K
  • Last Post
Replies
3
Views
1K
  • Last Post
Replies
2
Views
3K
Replies
14
Views
2K
  • Last Post
Replies
15
Views
16K
Replies
2
Views
3K
Replies
3
Views
5K
Replies
4
Views
284
Top