• Support PF! Buy your school textbooks, materials and every day products Here!

Electromotive force

  • Thread starter Xazdrubal
  • Start date
  • #1
1
0

Homework Statement



Atorch battery transfers 5200J of chemical energy into electrical energy while supplying a current of 0.25A for 4400 s. The bulb transfers 4800 j of electrical energy into heat and light during this time. Calculate
a)the charge that flows
b)the e.m.f. of the battery
c) the p.d. across the bulb
d)the lost volts

Homework Equations



Q=IT


The Attempt at a Solution


a) 0.25 x 4400 = 1100 C
b)5200/1100 = 4.73V
C) V=W/Q

NOT SURE WHAT TO DO FOR C / D /
 

Answers and Replies

  • #2
berkeman
Mentor
57,491
7,517

Homework Statement



Atorch battery transfers 5200J of chemical energy into electrical energy while supplying a current of 0.25A for 4400 s. The bulb transfers 4800 j of electrical energy into heat and light during this time. Calculate
a)the charge that flows
b)the e.m.f. of the battery
c) the p.d. across the bulb
d)the lost volts

Homework Equations



Q=IT


The Attempt at a Solution


a) 0.25 x 4400 = 1100 C
b)5200/1100 = 4.73V
C) V=W/Q

NOT SURE WHAT TO DO FOR C / D /
Welcome to the PF.

What does "p.d. across the bulb" mean? Power dissipated?

If so, then power is just total energy divided by time, right?

Once you have the bulb power, calculate the bulb voltage, and the difference between that and the battery source EMF is what is lost across the battery's internal resistance.
 

Related Threads on Electromotive force

  • Last Post
Replies
1
Views
937
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
1
Views
1K
  • Last Post
Replies
3
Views
575
  • Last Post
Replies
16
Views
1K
  • Last Post
Replies
2
Views
16K
  • Last Post
Replies
5
Views
713
Replies
2
Views
2K
Replies
1
Views
241
  • Last Post
Replies
7
Views
1K
Top