• We need your support!

    We are currently struggling to cover the operational costs of Xtremepapers, as a result we might have to shut this website down. Please donate if we have helped you and help make a difference in other students' lives!
    Click here to Donate Now (View Announcement)

Physics: Post your doubts here!

Messages
1,983
Reaction score
3,044
Points
273

Attachments

  • upload_2014-5-14_12-19-55.png
    upload_2014-5-14_12-19-55.png
    11.6 KB · Views: 3
Messages
1,983
Reaction score
3,044
Points
273
for definition emf should we write work done in driving a unit charge around a circuit or should we write chemical energy converted to electrical energy per unit charge?
it depends on the marks though. i have only seen energy converted into electric form of energy when in columb of charge passes through complete loop in markschemes
 
Messages
1,983
Reaction score
3,044
Points
273
after 1/4 T the wave will be a straight line. to see why the antinodes go back to their original position(complete one oscilation in one T) so in 1/4th they complete 1/4th of their oscillation. which is from max to zero, then from zero to min, then from min to zero then from zero to max.
120px-Standing_wave.gif
 
Messages
398
Reaction score
761
Points
73
after 1/4 T the wave will be a straight line. to see why the antinodes go back to their original position(complete one oscilation in one T) so in 1/4th they complete 1/4th of their oscillation. which is from max to zero, then from zero to min, then from min to zero then from zero to max.
120px-Standing_wave.gif
How would we draw that onto The Exam paper?
 
Messages
1,983
Reaction score
3,044
Points
273

Attachments

  • upload_2014-5-14_12-40-29.png
    upload_2014-5-14_12-40-29.png
    5.3 KB · Views: 13
Messages
515
Reaction score
1,447
Points
153
(a) P=V^2/R
R=V^2/P = (240)2/(1.5 x 10^3)
=38.4 ohms

(b)
when the powers r in series then we will add their reciprocals n when they r in parallel then we will add their values...
1. there will be no current so no power will generate
2. when S2 is closed then current will choose the low resistance path n will only flow through one heater.. so 1.5kW
3. all of them r closed.. no current is passing through B.. so we will simply add the powers that r in parallel with eachother.. 3 kW
4. the current is passing through A and B... so we will add the reciprocals of the powers n the ans will be 0.75 kW
5. Current is passing through all the heaters so... 0.75 + 1.5 = 2.25 kW
 
Top