Exam 17: Temperature and Heat

Induction: X and Y are two uncharged metal spheres on insulating stands, and are in contact with each other. A positively charged rod R is brought close to X as shown in Figure (a). Sphere Y is now moved away from X, as in Figure (b). What are the final charge states of X and Y?

Charge in an electric field: A small sphere with a mass of 441 g is moving upward along the vertical +y-axis when it encounters an electric field of 5.00 N/C . If, due to this field, the sphere suddenly acquires a horizontal acceleration of 13.0 m/s2 , what is the charge that it carries?

Charge in an electric field: What is the minimum magnitude of an electric field that balances the weight of a plastic sphere of mass that has been charged to

Coulomb's law: In the figure Q = 5.8 nC and all other quantities are accurate to 2 significant figures. What is the magnitude of the force on the charge Q? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

Charge in an electric field: A proton is placed in an electric field of intensity 700 N/C. What are the magnitude and direction of the acceleration of this proton due to this field? (m_proton = 1.67 × 10^-27 kg, e = 1.60 × 10^-19C)

Coulomb's law: The point charge at the bottom of the figure is Q = + 17 nC, and the curve is a circular arc. What is the magnitude of the force on the charge Q due to the other point charges shown? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

Multiple point-charges: A 3.0-μC positive point charge is located at the origin and a positive point charge is located at Find the coordinates of the point where the net electric field strength due to these charges is zero.

Coulomb's law: A positive point charge Q is fixed on a very large horizontal frictionless tabletop. A second positive point charge q is released from rest near the stationary charge and is free to move. Which statement best describes the motion of q after it is released?

Charge: A piece of plastic has a net charge of +2.00 μC. How many more protons than electrons does this piece of plastic have? (e = 1.60 × 10^-19C)

Coulomb's law: In the figure, charge = 3.1 × C is placed at the origin and charge is placed on the x-axis, at x = -0.20 m. Where along the x-axis can a third charge Q = -8.3 µC be placed such that the resultant force on this third charge is zero?

Coulomb's law: Two identical small conducting spheres are separated by 0.60 m. The spheres carry different amounts of charge and each sphere experiences an attractive electric force of 10.8 N. The total charge on the two spheres is -24 μC. The two spheres are now connected by a slender conducting wire, which is then removed. The electric force on each sphere is closest to

Dipoles: An electric dipole is made of two charges of equal magnitudes and opposite signs. The positive charge, q = 1.0 μC, is located at the point (x, y, z) = (0.00 cm, 1.0 cm, 0.00 cm), while the negative charge is located at the point (x, y, z) = (0.00 cm, -1.0 cm, 0.00 cm). How much work will be done by an electric field = (3.0 × 10⁶ N/C) to bring the dipole to its stable equilibrium position?

Charged ring: In the figure, a ring 0.71 m in radius carries a charge of + 580 nC uniformly distributed over it. A point charge Q is placed at the center of the ring. The electric field is equal to zero at field point P, which is on the axis of the ring, and 0.73 m from its center. (ε₀ = 8.85 × 10^-12 C²/N ∙ m²) The point charge Q is closest to

Multiple point-charges: Two point charges, Q₁ = -1.0 μC and Q₂ = + 4.0 μC, are placed as shown in the figure. (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²) The y component of the electric field, at the origin O, is closest to

Dipoles: An initially-stationary electric dipole of dipole moment = (5.00 × 10^-10 C ∙ m) placed in an electric field = (2.00 × 106 N/C) + (2.00 × 106 N/C) . What is the magnitude of the maximum torque that the electric field exerts on the dipole?

Multiple point-charges: Three equal negative point charges are placed at three of the corners of a square of side d. What is the magnitude of the net electric field at the center of the square? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

Motion of a charged particle: A pair of charged conducting plates produces a uniform field of 12,000 N/C, directed to the right, between the plates. The separation of the plates is 40 mm. An electron is projected from plate A, directly toward plate B, with an initial velocity of v_o = 2.0 × 10⁷ m/s, as shown in the figure. (e = 1.60 × 10^-19 C, ε₀ = 8.85 × 10^-12 C²/N ∙ m², m_el = 9.11 × 10^-31 kg) The velocity of the electron as it strikes plate B is closest to

Parallel plates: An electric field is set up between two parallel plates, each of area 2.0 m², by putting 1.0 μC of charge on one plate and -1.0 μC of charge on the other. The plates are separated by 4.0 mm with their centers opposite each other, and the charges are distributed uniformly over the surface of the plates. What is the magnitude of the electric field between the plates at a distance of 1.0 mm from the positive plate, but not near the edges of the plates? (ε₀ = 8.85 × 10^-12 C²/N ∙ m²)

Electric field of a single point-charge: A metal sphere of radius 10 cm carries a charge of +2.0 μC uniformly distributed over its surface. What is the magnitude of the electric field due to this sphere at a point 5.0 cm outside the sphere's surface? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

Dipoles: An electric dipole consists of charges ±5.00 µC separated by 1.20 mm. It is placed in a vertical electric field of magnitude 525 N/C oriented as shown in the figure. The magnitude of the net torque this field exerts on the dipole is closest to