The heat generated per second in a resistor with 230V a.c mains is 40J .What is the value of d.c for same heat

1 ⤊

The heat generated per second in a resistor with 230V a.c mains is 40J .What is the value of d.c for same heat

heating effect of current

2007-11-24 20:41:19 · 2 answers · asked by Binson 1 in Science & Mathematics ➔ Physics

2 answers

230 VDC

2007-11-24 20:51:52 · answer #1 · answered by Helmut 7 · 1⤊ 0⤋

helmut is right. When we say 230V a.c. it is implied the voltage is RMS meaning root mean square. The instantaneous voltage of a.c. is continuously changing from -something to +something and back. The RMS voltage is the integrated sum of all the voltages squared over time [the peak voltage is around 330V].

The reason RMS is used, is because wattage is current^2*R but current is voltage/R, therefor wattage is voltage^2/R. So using RMS equivalences wattage generated using an a.c source to the wattage generated by a d.c. source.

2007-11-24 21:16:39 · answer #2 · answered by mis42n 4 · 0⤊ 0⤋