Question

ᴄᴀʟᴄᴜʟᴀᴛᴇ ᴛʜᴇ ɴᴏ ᴏғ ᴇʟᴇᴄᴛʀᴏɴs ғʟᴏᴡɪɴɢ ᴛʜʀᴏᴜɢʜ ᴛʜᴇ ᴄʀᴏss sᴇᴄᴛɪᴏɴ ᴏғ ᴄᴏɴᴅᴜᴄᴛᴏʀ ᴡʜᴇɴ ᴄᴜʀʀᴇɴᴛ ᴏғ 20 ᴍA ғʟᴏᴡs ғᴏʀ 50 sᴇᴄᴏɴᴅs​

Answer 1

GiVEN :-

• Current (I) = 20 mA
• Time taken (t) = 50 seconds
• Charge of an electron (e) = 1.6 × 10⁻¹⁹ C

TO FiND :-

• Number of electrons (n) .

CALCULATiON :-

Convert the unit of current from mA to A

• ⇒ 1 mA = 0.001 A
• ⇒ 20 mA = 20(0.001)
• ⇒ 0.02 A

Now, we know that :-

I = Q/t

⇒ I = ne/t

• ⇒ 0.02 = (n × 1.6 × 10⁻¹⁹)/50
• ⇒ 0.02(50) = 1.6 × 10⁻¹⁹ n
• ⇒ 1 = 1.6 × 10⁻¹⁹ n
• ⇒ n = 1/(1.6 × 10⁻¹⁹)
• ⇒ n = 1/1.6 × 1/10⁻¹⁹
• ⇒ n = 0.625 × 10¹⁹
• ⇒ n = 6.25 × 10¹⁸

FiNAL AÑSWER :-

• 6.25 × 10¹⁸ electrons are flowing through the cross section of the conductor

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Answer 2

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• I = ne/t
• 0.02 = (n × 1.6 × 10⁻¹⁹)/50
• 0.02(50) = 1.6 × 10⁻¹⁹ n
• 1 = 1.6 × 10⁻¹⁹ n
• n = 1/(1.6 × 10⁻¹⁹)
• n = 1/1.6 × 1/10⁻¹⁹
• n = 0.625 × 10¹⁹
• n = 6.25 × 10¹⁸

6.25 × 10¹⁸ electrons are flowing through the cross section of the conductor