Question

a bulb is rated at 200v-100w what is it resistance five such bulbs burn for 4 hours what is the electric energy consumed calculate the cost if its rate is 4.50 per unit​

Answer 1

Answer:

https://www.toppr.com/ask/question/a-an-electric-bulb-is-rated-at-200v100w-what-is-its-resistance-five-such-bulbs/

Explanation:

Check the answer by clicking the link frnds

Answer 2

✰Solution

(a) Calculation of Resistance. Here we know the voltage and power of the bulb. So, the resistance can be calculated by using the formula :

$\begin{gathered}\sf\: \: \: \: \: \: \: P = \frac{v {}^{2} }{r} \\ \\ Here, \: Power, \: P = 100 \: watts \\ \\ \: \: \: \: \: \: \: \: \: \sf Voltage, \: V = 200 \: volts \\ \\\sf And, \: Resistance, \: R = \ \ \: ? \\ \sf (To \: be \: Calculated \: ) \\ \\ \sf Now, \: putting \: these \: values \: in \: the \\ above \: formula \: we \: get : \\ \\\sf 100 = \frac{(200) {}^{2} }{R} \\ \\ 100 \: R = 40000 \\ \\ \sf And, \: R = \frac{40000}{100} \\ \\ \: \: \: \: \: \: \: \: \: \: \: \: = 400 \: ohms \\ \\ (b) \:\bf Calculation \: of \: Electrical \: Energy \\\bf Consumed. \: the \: Electrical \: energy \\consumed \: in \: kilowatts - hours \\\bf can \: be \: calculated \: by \: using \: the \: \\ formula: \\ \\ \: \: E = P \times T \\ \\ \sf Here, \: power, \: P = 100 \: watts \\ \\ \: \:=\sf \frac{100}{1000} kilowatts \\ \\ \: \: = 0.1 \: kilowatt \: \: \: \: ...(1) \\ \\\sf And, \: time, \: T = 4 \: hours \: \: \: \: ...(2) \\ \\\sf So, \: Energy \: consumed \: by \: 1 \: bulb \\ \: \: = 0.1 \times 4 \\ \\ \: \: \sf= 0.4 \: kilowatts - hours \\ \\\sf And, \: energy \: consumed \: by \: 5 \: bulbs \: \\ \: \: = 0.4 \times 5 \\ \\ \: \: = 2 \: kilowatts - hours \\ \\ \sf Thus, \: the \: total \: electrical \: energy \: \\ consumed \: is: \\ (2 \: kilowatts - hours )or (2 \: units). \\ \\\sf (c) \: \sf calculation \: of \: cost \: of electrical \: \\\sf \:energy. We \: have \: been \: \\ \sf \:given \: that: \\ \\\sf cost \: of \: 1 \: unit \: of \: electricity \\ \: \: = 4.60 \: rs \\ \\\sf So, \: \: cost \: of \: 1 \: of \: electricity \\ \sf\: \: = 4.60rs \times 2 \sf\: rs \\ \\\sf \: \: = 9.20 rs \: \: \: \: \: \: \: (Answer)\end{gathered}$