Question

An electric heater consumes 4,4 kW power when connected with a 220 V line voltage then,
current
6)
Calculate the current passing through the heater.
Calculate the energy consumed in 2 hours.
(iii) Calculate resistance of a heater.​

Answer 1

Given

An electric heater consumes 4.4 kW power when connected with a 220 V line voltage

To Find

(i) Calculate the current passing through the heater

(ii) Calculate the energy consumed in 2 hours

(iii) Calculate resistance of a heater

Solution

Given that

An electric heater consumes 4.4 kW power when connected with a 220 V line voltage

Hence

Power (P) = 4.4 kW = 4.4 x 1000 W

Voltage (V) = 220 V

(i)

$\rm \longrightarrow I=\dfrac{P}{V}$

Here

• I = current
• P = power
• V = voltage

$\rm \longrightarrow I=\dfrac{4.4 \times 1000}{220} \ A$

$\rm \longrightarrow I=20 \ A$

(ii)

$\rm \longrightarrow E=I^{2}Rt$

Here

• E = energy
• I = current
• R = resistance
• t = time

$\sf \longrightarrow E=(20)^{2} \times 11 \times 2 \times 60 \times 60x^{2} \ J$

$\sf \longrightarrow E=400 \times 11 \times 7200 \ J$

$\sf \longrightarrow E=4400\times 7200 \ J$

$\sf \longrightarrow E=31680000 \ J$

$\sf \longrightarrow E=3.168 \times 10^{7} \ J$

(iii)

$\rm \longrightarrow R=\dfrac{V}{I}$

Here

• R = resistance
• V = voltage
• I = current

$\rm \longrightarrow R=\dfrac{220}{20} \ \Omega$

$\rm \longrightarrow R=11 \ \Omega$

Answer 2

GIVEN :-

• Aɴ ᴇʟᴇᴄᴛʀɪᴄ ʜᴇᴀᴛᴇʀ ᴄᴏɴsᴜᴍᴇs 4.4 ᴋᴡ ᴘᴏᴡᴇʀ .

• Tʜᴇ ᴇʟᴇᴄᴛʀɪᴄ ʜᴇᴀᴛᴇʀ ᴄᴏɴɴᴇᴄᴛᴇᴅ ᴡɪᴛʜ ᴀ 220V ʟɪɴᴇ ᴠᴏʟᴛᴀɢᴇ .

TO FIND :-

1. Tʜᴇ ᴄᴜʀʀᴇɴᴛ ᴘᴀssɪɴɢ ᴛʜʀᴏᴜɢʜ ᴛʜᴇ ʜᴇᴀᴛᴇʀ .
2. Tʜᴇ ᴇɴᴇʀɢʏ ᴄᴏɴsᴜᴍᴇᴅ ɪɴ 2 ʜᴏᴜʀs .
3. Tʜᴇ ʀᴇsɪsᴛᴀɴᴄᴇ ᴏғ ʜᴇᴀᴛᴇʀ .

SOLUTION :-

[1]

$\huge\blue\star$ $\bf\pink{Current(I)\:=\:\dfrac{Power(P)}{Voltage(V)}\:}$

ᴡʜᴇʀᴇ,

• $\bf\red{P}$ = 4.4 KW = 4.4 × 1000 = 4400W

• $\bf\red{V}$ =220 V

➳ Current(I) = 4400/220

➳ Current(I) = 20 A

$\huge\red\therefore$ Tʜᴇ ᴄᴜʀʀᴇɴᴛ ᴘᴀssɪɴɢ ᴛʜʀᴏᴜɢʜ ᴛʜᴇ ʜᴇᴀᴛᴇʀ is "20A" .

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[2]

$\huge\gray\star$ $\bf\pink{Energy(E)\:=\:I^2\:R\:t\:}$

ᴡʜᴇʀᴇ,

• $\bf\red{I}$ = 20 A

• $\bf\red{R}$ = V/I = 220/20 = 11 Ω

• $\bf\red{t}$ = 2hrs = 2 × 60 × 60 = 72 s

➳ Energy (E) = (20)² × 11 × 72

➳ Energy (E) = 400 × 792

➳ Energy (E) = 316800 J

$\huge\red\therefore$ Tʜᴇ ᴇɴᴇʀɢʏ ᴄᴏɴsᴜᴍᴇᴅ ɪɴ 2 ʜᴏᴜʀs is "316800J" .

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[3]

$\huge\purple\star$ $\bf\pink{Resistance(R)\:=\:\dfrac{V}{I}\:}$

ᴡʜᴇʀᴇ,

• $\bf\red{I}$ = 20 A

• $\bf\red{V}$ = 220 V

➳ Resistance(R) = 220/20

➳ Resistance(R) = 11 Ω

$\huge\red\therefore$ Tʜᴇ ʀᴇsɪsᴛᴀɴᴄᴇ ᴏғ ʜᴇᴀᴛᴇʀ is "11Ω" .

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