How Much Energy Does a Lamp Dissipate with a 0.3 A Current and 6 V Power Supply?

  • Thread starter Thread starter blackout85
  • Start date Start date
  • Tags Tags
    Physics
Click For Summary
SUMMARY

A lamp dissipates 216 Joules of energy when a current of 0.3 A is passed through it for 2 minutes using a 6 V power supply. The calculations confirm that the charge (Q) is 36 Coulombs, derived from the equation I=Q/t, where I is the current and t is the time in seconds. The energy (E) is then calculated using the formula E=QV, resulting in E=216 J. This method effectively demonstrates the relationship between current, voltage, and energy dissipation in electrical circuits.

PREREQUISITES
  • Understanding of basic electrical concepts such as current, voltage, and charge.
  • Familiarity with the equations I=Q/t and E=QV.
  • Knowledge of units of measurement for electrical energy (Joules, Amperes, Volts).
  • Basic grasp of power calculations in electrical circuits.
NEXT STEPS
  • Study the relationship between power, current, and voltage using the formula P=IV.
  • Learn about energy dissipation in resistive circuits and the role of resistance.
  • Explore the concept of electrical energy consumption over time and its implications.
  • Investigate the efficiency of different types of lamps and their energy usage.
USEFUL FOR

Students in electrical engineering, hobbyists experimenting with circuits, and anyone interested in understanding energy dissipation in electrical devices.

blackout85
Messages
27
Reaction score
1
A current of 0.3 A is passed through a lamp for 2 minutes using a 6 V power supply. The electrical energy dissipated by this lamp during the two minutes is:
a) 1.8 J
b) 12 J
c) 20J
d) 36 J
e) 216 J

If someone could just help me to start off that would be great.
The main equations I have to use are

I=Q/t
E= QV

(.3A)= (Q)/(120)
Q= 36

E= (36)(6V)
E=216 J

Am I right:confused:
 
Physics news on Phys.org
looks good, tho ordinarily the power/heat would first be calculated as I*V, then multiplied by 120
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

Similar threads

  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 20 ·
Replies
20
Views
5K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 5 ·
Replies
5
Views
9K
Replies
4
Views
5K
  • · Replies 8 ·
Replies
8
Views
5K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
Replies
1
Views
2K