Question

An electric bulb of 60 W is used for 6 h per day. Calculate the ‘units’ of energy consumed in one day by the bulb.

Answer 1

Answer :-

0.36 ‘units’.

Explanation :-

Given :

Power of electric bulb = 60 W = 0.06 kW

Time used, t = 6 h

To Find :

The “units” of energy = ?

Solution :

We know,

$\boxed{\sf{}Energy=Power\times Time\ taken}$

Put their values and solve it.

= 0.06 kW × 6 h

= 0.36 kW h

Electric consumption in households is measured in kWh and generally called unit. Therefore, 1 unit of electricity is equal to 1kWh.

= 0.36 ‘units’.

Hence,the energy consumed by the bulb is 0.36 ‘units’.

☆Know more☆

• Rate of doing work is called power.

• The SI unit of power is ‘Watt’

• Capacity of doing work is called energy.

• S.I unit of energy is joule and is denoted by ‘J’.
• Commercial unit of energy is kilo Watt hour and is written as kWh.

Answer 2

GIVEN :-

• Tʜᴇ ᴘᴏᴡᴇʀ ᴏғ ᴀɴ ᴇʟᴇᴄᴛʀɪᴄ ʙᴜʟʙ ɪs 60W .

• Tʜᴇ ᴇʟᴇᴄᴛʀɪᴄ ʙᴜʟʙ ɪs ᴜsᴇᴅ ғᴏʀ 6ʜrs ᴘᴇʀ ᴅᴀʏ .

TO FIND :-

• Tʜᴇ ᴜɴɪᴛ ᴏғ ᴇɴᴇʀɢʏ ᴄᴏɴsᴜᴍᴇᴅ ɪɴ ᴏɴᴇ ᴅᴀʏ ʙʏ ᴛʜᴇ ʙᴜʟʙ .

SOLUTION :-

$\huge\red\star$ $\bf\purple{Energy\:=\:Power\times{Time}\:}$

ᴡʜᴇʀᴇ,

• ᴘᴏᴡᴇʀ = 60W = 60/1000 = 0.06 KW

• Tɪᴍᴇ = 6 ʜrs

➳ Eɴᴇʀɢʏ = 0.06 × 6

➳ Eɴᴇʀɢʏ = 0.36 KW.h

➳ Eɴᴇʀɢʏ = 0.36 units

$\huge\red\therefore$ Tʜᴇ ᴜɴɪᴛ ᴏғ ᴇɴᴇʀɢʏ ᴄᴏɴsᴜᴍᴇᴅ ɪɴ ᴏɴᴇ ᴅᴀʏ ʙʏ ᴛʜᴇ ʙᴜʟʙ ɪs "0.36 ᴜɴɪᴛs" .

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ɪᴍᴘᴏʀᴛᴀɴᴛ ᴘᴏɪɴᴛs :-

$\huge\green\bullet$ 1 ᴋɪʟᴏᴡᴀᴛᴛ.ʜᴏᴜʀ (KW.h) ɪs ᴄᴏᴍᴍᴇʀᴄɪᴀʟ ᴜɴɪᴛ ᴏғ ᴇʟᴇᴄᴛʀɪᴄᴀʟ ᴇɴᴇʀɢʏ .

$\huge\green\bullet$ Iᴛ ɪs ᴀʟsᴏ ᴅᴇғɪɴᴇᴅ ᴀs "1 ᴜɴɪᴛ" .

$\huge\green\bullet$ Eʟᴇᴄᴛʀɪᴄɪᴛʏ ʙɪʟʟs ᴀʀᴇ ᴄᴀʟᴄᴜʟᴀᴛᴇᴅ ɪɴ ᴛʜᴇ ᴜɴɪᴛs ᴏғ ᴇɴᴇʀɢʏ ᴄᴏɴsᴜᴍᴇᴅ .

$\huge\green\bullet$ Sᴏ, ᴛʜᴇ kilowatt-hour ɪs ᴄᴏᴍᴍᴏɴʟʏ ᴜsᴇᴅ ᴀs ᴀ ʙɪʟʟɪɴɢ ᴜɴɪᴛ ғᴏʀ ᴇɴᴇʀɢʏ ᴅᴇʟɪᴠᴇʀᴇᴅ ᴛᴏ ᴄᴏɴsᴜᴍᴇʀs ʙʏ ᴇʟᴇᴄᴛʀɪᴄ ᴜᴛɪʟɪᴛɪᴇs .