DT 1 (12th Grade) MB2 Physics

An electron is at a distance of 0.50 x 10^-10 m from a proton.

[Data: e = 1.6 x 10^-19 C ; m_e, = 9.1 x 10^-31 kg; m_p, = 1.67 x 10^-27 kg; G = 6.67 x 10^-11 N . m²/kg²].

What is the electrical force exerted on the electron by the proton and what is the gravitational force between these particles?

• The electric force between the electron and proton is 9.2 x 10^-8 N, while the gravitational force is 4.05 x 10^-47 N.

• The electric force between the electron and proton is 4.05 x 10^-47 N, while the gravitational force is 9.2 x 10^-8 N

• The electric force between the electron and proton is 6.67 x 10^-11 N, while the gravitational force is 1.6 x 10^-19 N.

• The electric force between the electron and proton is 1.6 x 10^-19 N, while the gravitational force is 6.67 x 10^-11 N.

• The electric force between the electron and proton is 8.99 x 10⁹ N, while the gravitational force is 6.67 x 10^-11 N.

Two charges are located on the x-axis with q₁ = 2.3 x 10^-8 C at the origin, and with

q₂ = -5.6 x 10^-8 C at x = 1.30 m (see Fig. 3-4). Find the force exerted by these two charges on a third charge of q = 3.3 x 10-8 C, which is located at: (a) x = 0.24 m on the x axis and (b) x = 1.55 m on the x axis.

• (a) 1.34 x 10^-4 N in the positive x-direction; (b) (2.66-0.03) x 10^-4 N in the negative x-direction.

• (a) (2.66-0.03) x 10^-4 N in the negative x-direction; (b) 1.34 x 10^-4 N in the positive x-direction.

• (a) 1.34 x 10^-4 N in the positive x-direction; (b) 1.34 x 10^-4 N in the positive x-direction.

• (a) (2.66-0.03) x 10^-4 N in the negative x-direction; (b) (2.66-0.03) x 10^-4 N in the negative x-direction.

• None of the answers.

A charge of 2.5 x 10^-8 C is located at the origin. What electric field (magnitude and direction) does this charge produce at a point on the x-axis at x = 0.87 m?

• 2.5 x 10⁸ N/C in the positive x-direction

• 2.5 x 10⁸ N/C in the negative x-direction

• 2.97 x 10² N/C in the positive x-direction

• 2.97 x 10² N/C in the negative x-direction

Two positive charges are located a distance of 0.58 m apart on the x axis. At the origin,

the charge is 5.5 x 10^-8 C, and at x = 0.58 the charge is 3.3 x 10^-8 C. At what point is the electric field

equal to zero?

• x = 0.58 m

• x = 0.33 m

• x = 0.25 m

• x = 0.42 m

• x = 0.48 m

Two charges, Q₁= 3.3 x 10^-6 C and Q₂ = -5.1 x 10^-6C are located at the origin and

at x = 0.36 cm, respectively. A third charge, q = 9.3 x 10^-7 C, is moved from far away ( r = ∞) to a

point on the y axis, y = 0.48 cm. What is the potential energy between q and Q₁ at this point?

• 3.09 J

• 5.75 J

• -5.75 J

• 0.48 J

• -0.48 J

A proton is moving directly toward a fixed nucleus containing 23 protons. The speed of

the proton when it is at a distance of 5.8 x 10^-9 m from the nucleus is 2.4 x 10⁶ m/s. The proton has a

charge of 1.6 x 10^-19 C and a mass of 1.67 x 10^-27 kg. What was its kinetic and potential energy at this initial distance?

• Kinetic Energy: 9.14 x 10^-19 J, Potential Energy: 4.81 x 10^-15 J

• Kinetic Energy: 4.81 x 10^-15 J, Potential Energy: 9.14 x 10^-19 J

• Kinetic Energy: 0 J,

  Potential Energy: 0 J

• Kinetic Energy: 1.6 x 10^-19 J, Potential Energy: 0 J

• Kinetic Energy: 0 J, Potential Energy: 1.6 x 10^-19 J

Four charged particles are placed at the corners of a square of side 0.39 m. The particles have charges of 2.3 μC, -5.6 μC, 7.9 μC and - 1.3 μC as in Fig. 4-9. How much work was done by outside forces to place those particles in their positions if they were originally very far away?

• -0.71 J

• 0.71 J

• -1.21 J

• 1.21 J

• 0 J