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Murrr4er [49]
3 years ago
14

A solid conducting sphere of radius 2 cm has a charge of 8microCoulomb. A conducting spherical shell of inner radius 4 cm andout

er radius 5 cm is concentric with the solid sphere and has acharge of -4 microCoulomb. What is the magnitude and direction ofthe electric field at r = 7 cm?
A)0

B)1 N/C radially outward

C)7.35 106 N/C radiallyoutward

D)7.35 106 N/C radiallyinward

E)3.56 107 N/C radiallyoutward

F)8 107 N/C radially outward
Physics
1 answer:
nika2105 [10]3 years ago
6 0

Answer:

C) 7.35*10⁶ N/C radially outward

Explanation:

  • If we apply the Gauss'law, to a spherical gaussian surface with radius r=7 cm, due to the symmetry, the electric field must be normal to the surface, and equal at all points along it.
  • So, we can write the following equation:

       E*A = \frac{Q_{enc} }{\epsilon_{0}} (1)

  • As the electric field must be zero inside the conducting spherical shell, this means that the charge enclosed by a spherical gaussian surface of a radius between 4 and 5 cm, must be zero too.
  • So, the +8 μC charge of  the solid conducting sphere of radius 2cm, must be compensated by an equal and opposite charge on the inner surface of the conducting shell of total charge -4 μC.
  • So, on the outer surface of the shell there must be a charge that be the difference between them:

        Q_{enc} = - 4e-6 C - (-8e-6 C) = + 4 e-6 C

  • Replacing in (1) A = 4*π*ε₀, and Qenc = +4 μC, we can find the value of E, as follows:

      E = \frac{1}{4*\pi*\epsilon_{0} } *\frac{Q_{enc} }{r^{2} } = \frac{9e9 N*m2/C2*4e-6C}{(0.07m)^{2} } = 7.35e6 N/C

  • As the charge that produces this electric field is positive, and the electric field has the same direction as the one taken by a positive test charge under the influence of this field, the direction of the field is radially outward, away from the positive charge.
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Answer:

0.705 m/s²

Explanation:

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Using newton's law of motion:

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v = 35 km/h = 9.72 m/s, u = 35 km/h = 9.72 m/s, s = 88 m

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9.72² = 9.72² + 2a(88)

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Explanation:

The height from which the student tosses the ball to a friend, h = 3.8 meters above the friend

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Given that the ball is tossed in the horizontal direction, and not the vertical direction, the initial vertical component of the velocity of the ball = 0

The equation of the vertical motion of the ball can therefore, be represented by the free fall equation as follows;

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