Basic electricity & incandescent bulb numericals

  • Thread starter Thread starter flabber
  • Start date Start date
  • Tags Tags
    Bulb Electricity
Click For Summary
SUMMARY

This discussion focuses on basic electricity concepts related to incandescent bulbs and numerical problems involving voltage, power, and resistance. Key questions include calculating the number of cells needed to power a 12V, 24W tungsten filament bulb, determining which of three bulbs (40W, 60W, 100W) burns brightest in series and parallel configurations on a 220V mains, calculating energy consumption of a 20V, 500W electric iron over 24 hours, and finding the heat generated by a 40W bulb in one hour. Participants are encouraged to post separate threads for each question and to include relevant equations and initial attempts at solutions.

PREREQUISITES
  • Understanding of Ohm's Law (V = IR)
  • Knowledge of power calculations (P = VI)
  • Familiarity with series and parallel circuits
  • Basic principles of energy consumption (kWh calculation)
NEXT STEPS
  • Learn how to calculate the number of cells needed for specific voltage requirements in circuits.
  • Study the differences in brightness of bulbs in series versus parallel configurations.
  • Research energy consumption calculations for electrical appliances over time.
  • Explore the relationship between power, heat generation, and time for electrical devices.
USEFUL FOR

Students, educators, and hobbyists interested in basic electricity principles, particularly those working with incandescent bulbs and circuit calculations.

flabber
Messages
4
Reaction score
0
hi there, i have few questions:

1. A 12V, 24W tungsten filament bulb is supplied with current from n cells connected in series. Each cell has an emf of 1.5V and internal resistance of 0.25. What is the value of n in order that the bulb runs at its rated power?

2. Three bulbs are rating 40W, 60W, 100W designed to work on 220V mains. Which bulb will burn most brightly if they are connected in SERIES across 220V mains? Repeat the same question when they are connected in PARALLEL across 220V.

3. An electric iron is marked 20 Volts, 500W. what will be The units consumed by it in using it for 24 hours?

4. What is the heat generated by a 40 W bulb in one hour?

please someone help me wid these numericals, i wud be highly grateful!
 
Physics news on Phys.org
Show some workout.
Can you find out the relation between V, W, I and R?
 
flabber, welcome to PF :smile:

In addition to showing your own efforts towards solving the problem, please post separate questions in separate threads. If we had 4 problem discussions all running at once, it would be too confusing to follow.

I'll suggest you make 4 separate new posts, one for each problem. Also, please show what equations you think are relevant (as rl.bhat suggested), and show your own attempt or start toward solving each problem.
 
Last edited:

Similar threads

Incandescent Bulb - suitable approximation for voltage-current curve
  • · Replies 2 ·
Replies
2
Views
1K
3 bulbs at different brightness
  • · Replies 4 ·
Replies
4
Views
2K
# of elecron/sec in a 3 bulb circuit
  • · Replies 3 ·
Replies
3
Views
3K
High School The relationship between brightness of bulb and power rating
  • · Replies 14 ·
Replies
14
Views
7K
Graduate Edison effect for Incandescent Bulb?
  • · Replies 3 ·
Replies
3
Views
5K
Solve Open Circuit Problem 3: Two Batteries and 3 Bulbs
  • · Replies 4 ·
Replies
4
Views
20K
Electrostatic physics: can someone check my answers?
  • · Replies 1 ·
Replies
1
Views
3K
Is it safe to run laptop and router on modified sine wave inverter?
  • · Replies 3 ·
Replies
3
Views
17K
Calculating Current and Energy in Circuit with Resistors and Batteries
  • · Replies 7 ·
Replies
7
Views
3K