Answer / tripti kumari

first we find the resistance of the lamp that is given by formula p=V*V/R
R=230*230/200=264.5 ohm
now current flow through the lamp when connected to the supply 115 V that is
I=V/R
I=115/264.5=0.435
now power draw by the lamp given by
p=V*I=115*0.435=50.025
so it is slightly more than 50 W.

Answer / roy

find amp draw (200W/230V); find resistance 230V/amp draw; find amps at 115V; I^2*R=Power consumed. 50.2Watts

Answer / satheesh

The above answer is also wrong and Ist answer i
correct.Since the bulb is rated for 230 V and the power is
200W only at rated voltage.So the resistance is constant for
this rating.v2/w=230^2/200=264.5 ohms.If we apply 115 V also
this resistance will not vary.So the current drawn at this
time is v/R=I=115/264.5=0.435A=So definitely power = V*I
115*.435=50 Watts.

Answer / pratik khodake

The correct answer is slightly more than 50W.

Answer / sachin prajapati

(1) R=V1^2/P=230^2/200=264.5
V2=115
P=V2^2/R=115^2/264.5=50W
(2) R=264.5
I2=V2/R=115/264.5=0.435
P=V2I2=115×0.435=50.025W
So answer can both

Answer / raghavendran.r

The above mentioned answer is wrong.Plz do remember that at any condition the power consumes by an equipment will not change from its designed value.
If you are operating a system at reduced voltage then to meet with the power requirement it will consume more current, rather than operate at less power.
So if the voltage is reduced by half, the current has to increase accordingly.
V*I = P;then 230*I = 200;I = .87A.
for V = 115 then current = 1.732A.

what is mean by harmonics?Type of harmonics?

6 Answers  

I am shobana from Chennai. I am having my personal interview on 19th Dec at Chennai.kindly mail me the questions to mail id shobana.shanthi@gmail.com

0 Answers   Avalon, KK Capital,

What is warm / cold start of HT motors. How many warm start & cold start are possible in a day?

0 Answers  

Pls say , how we calculate lux / sq.ft, which formula used for calculation

5 Answers  

raleigh method

0 Answers  

At which time Synchronous generator act as a Synchronous Condenser?

4 Answers  

Why is the earth socket in an electrical plug outlet made thicker and lenghty?

5 Answers  

In 110V DC supply,if a closed circuit gets open, How can we identify the voltage which is measured after the resistor(4KOhm) which is open with negative.it shows 55V +ve when measured, also the actual positive source is 55V +ve .Because there is no voltage drop in open circuit. How can we identify whether this is the voltage which is series with the resistor or the DC source direct +ve.

1 Answers   GE,

In dc motor starter there is less voltage required for holding contactor that's may why it is called no volt coil. but in ac starter why holding contactor is called no volt coil.

2 Answers   JSW,

What is the battery voltage limit

3 Answers  

Define unilateral circuit?

0 Answers  

What is the value of specific gravity in charged lead acid batteries.

11 Answers