Two bulbs of 100 W and 40 W, rated at the same voltage are connected parallel to a supply. The current through the 100 W bulbs is 5 A. The current through the 40 W bulb is ----- A *
Answers
Explanation:
Rating of bulbs hasn't been specified which is very important. Assuming each bulb is rated at 120V supply when connected across rated voltage i.e.120V supply then power dissipation across bulb will be 40W (or 100W). Rating is important because if 40W bulb rated at 120V supply is connected across 200V supply then it will not work (might burn or blow up), meaning a device can not work at a voltage much higher than its rated voltage.
Resistance of bulb is inversely proportional to its rated power, at same voltage because
P=(V*V)/R
Therefore R (40W bulb) > R (60W bulb) > R (100W bulb). Hence the bulb across which power dissipation is more will glow brighter.
When connected in series: In a series connection, current flowing across each element in circuit is same. So when 40W bulb, 60W bulb and 100W bulb are connected in series, same current will flow through them. The power dissipation across each of them will determine which bulb will glow brighter. From the relation P=(I*I) R, since current is same the power dissipation will be higher for the bulb with higher resistance i.e. 40W bulb.
Hence 40W bulb will glow brighter in series connection.
2. When connected in parallel: In a parallel connection, voltage across each element is same. So when 40W bulb, 60W bulb and 100W bulb are connected in parallel, voltage across them will be same (200 V in the given case). The power dissipation across each of them will determine which bulb will glow brighter. From the relation P=(V*V)/R, since voltage is same the power dissipation will be higher for the bulb with lower resistance i.e. 100W bulb.
Hence 100W bulb will glow brighter in parallel connection.
So always remember if bulbs are connected in parallel, the bulb with higher rated power will glow brighter and if they are connected in series, the bulb with lower rated power will glow brighter
hope its correct and if its correct then it helps you..agar aap brainliest me mark nhi karoge vo to koi nhi bss apki help hojaye...its ok
Answer:
V=IR
Hence by that formula.... the answer is
5*40/100 i. e. 2A