A +35 µC point charge is placed 46 cm from an identical +35 µC charge. How much work would be required to move a +0.50 µC test charge from a point midway between them to a point 12 cm closer to either of the charges?

Answer :

Answer:

512.5 mJ

Explanation:

Let the two identical charges be q = +35 µC and distance between them be r₁ = 46 cm. A charge q' = +0.50 µC located mid-point between them is at r₂ = 46 cm/2 = 23 cm = 0.23 m.

The electric potential at this point due to the two charges q is thus

V = kq/r₂ + kq/r₂

= 2kq/r₂

= 2 × 9 × 10⁹ Nm²/C² × 35 × 10⁻⁶ C/0.23 m

= 630/0.23  × 10³ V

= 2739.13 × 10³ V

= 2.739 MV

When the charge q' is moved 12 cm closer to either of the two charges, its distance from each charge is now r₃ = r₂ + 12 cm = 23 cm + 12 = 35 cm = 0.35 m and r₄ = r₂ - 12 cm = 23 cm - 12 cm = 11 cm = 0.11 cm.

So, the new electric potential at this point is

V' = kq/r₃ + kq/r₄

= kq(1/r₃ + 1/r₄)

= 9 × 10⁹ Nm²/C² × 35 × 10⁻⁶ C(1/0.35 m + 1/0.11 m)

= 315 × 10³(2.857 + 9.091) V

= 315 × 10³ (11.948) V

= 3763.62 × 10³ V

= 3.764 MV

Now, the work done in moving the charge q' to the point 12 cm from either charge is

W = q'(V' - V)

= 0.5 × 10⁻⁶ C(3.764 MV - 2.739 MV)

= 0.5 × 10⁻⁶ C(1.025 × 10⁶) V

= 0.5125 J

= 512.5 mJ

Work done will be:  [tex]512.5 \mu J[/tex].

Given:

q = +35 µC

q' = +0.50 µC

r₁ = 46 cm

r₂ = 46 cm/2 = 23 cm = 0.23 m

The electric potential at this point due to the two charges q is thus

[tex]V = \frac{kq}{r_2}+\frac{kq}{r_2}\\\\ V= \frac{2kq}{r_2}\\\\V= \frac{2 * 9 * 10^9Nm^2/C^2 * 35 * 10^{-6} C}{0.23 m}\\\\V= \frac{630}{0.23*10^3}V\\\\V= 2739.13 * 10^3 V\\\\V= 2.739 \mu V[/tex]

When the charge q' is moved 12 cm closer to either of the two charges, its distance from each charge is now;

r₃ = r₂ + 12 cm = 23 cm + 12 = 35 cm = 0.35 m and

r₄ = r₂ - 12 cm = 23 cm - 12 cm = 11 cm = 0.11 cm.

Thus, the new electric potential at this point is

[tex]V' = \frac{kq}{r_3} + \frac{kq}{r_4}\\\\V= kq(\frac{1}{r_3}+\frac{1}{r_4})\\\\V= 9 * 10^9 Nm^2/C^2 * 35 * 10^{-6} C (\frac{1}{0.35m}+\frac{1}{0.11m})\\\\V= 315 * 10^3(2.857 + 9.091) V\\\\V= 315 * 10^3 (11.948) V\\\\V= 3763.62 * 10^3 V\\\\V= 3.764 \mu V[/tex]

Now, the work done in moving the charge q' to the point 12 cm from either charge is:

[tex]W = q'(V' - V)\\\\W= 0.5 * 10^{-6} C(3.764 MV - 2.739 MV)\\\\W= 0.5 *10^{-6} C(1.025 * 10^6) V\\\\W= 0.5125 J\\\\W= 512.5 \mu J[/tex]

Thus, the work done will be: [tex]512.5 \mu J[/tex].

Find out more information on "Work done" here:

brainly.com/question/25573309

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