Electrical Engineering - Energy and Power - Discussion
Discussion Forum : Energy and Power - General Questions (Q.No. 1)
1.
A 33 
half-watt resistor and a 330 half-watt resistor are connected across a 12 V source. Which one(s) will overheat?
half-watt resistor and a 330 half-watt resistor are connected across a 12 V source. Which one(s) will overheat?33
330
both resistors
neither resistor
Discussion:
58 comments Page 5 of 6.
Himanshu said:
1 decade ago
Option d is correct as both are taking same power and are connected in parallel (as given in question they are conected across 12 we supply. Across means parallel).
Arti said:
1 decade ago
Heat generated = (square of current)* Resistance * time
This means higher the current, more is the heat generated.
For 33ohms resistance across 12 V source, current is 0.36A.Hence heat generated per second will equal to 4.28 joules.
For 330 ohms resistance across 12V source, current is 0.036A. So heat generated per second= 0.436 joules.
Hence Option A is correct.
This means higher the current, more is the heat generated.
For 33ohms resistance across 12 V source, current is 0.36A.Hence heat generated per second will equal to 4.28 joules.
For 330 ohms resistance across 12V source, current is 0.036A. So heat generated per second= 0.436 joules.
Hence Option A is correct.
Biswajit said:
1 decade ago
What is half-watt resistor ?
Latha said:
1 decade ago
@Arti then how do you consider the wattage of resistance?
Sam said:
1 decade ago
Both the resistors have equal ratings.
Suresh Maniar said:
1 decade ago
Both Resistances are Connected across same voltage of 12V.
Wattage=V square/R since V=Const or same for both smaller are value shall draw more power and heat up more.
Wattage=V square/R since V=Const or same for both smaller are value shall draw more power and heat up more.
Dayo said:
1 decade ago
Both resistors are connected in series, therefore same voltage flow across each of them & there s also balance in heat dissipated by each.
Akhilesh pandit said:
1 decade ago
Power consumed by each of them is same so both of them get equally heated.
Sagar singh said:
1 decade ago
Since they are connected in parallel and 33 ohm is very less than 330 ohm more current will flow through 33 ohm, and therefore more heat will dissipate across 33 ohm and it gets over heated.
Syeda Jafri said:
1 decade ago
Heating depends upon the amount of current flowing through each resistance, not on power. If considered in parallel arrangement, 33 ohm resistance has higher current flow so it should get overheated & option A should be correct.
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