Exam 19: Electric Charges, Forces, and Fields

Three equal negative point charges -q are placed at three of the corners of a square of side d as shown in the figure.Which one of the arrows shown represents the direction of the net electric field at the vacant corner of the square?

The figure shows two unequal charges,+q and -Q.Charge -Q has greater magnitude than charge +q.Point X is midway between the charges.In what section of the line will there be a point where the resultant electric field is zero?

The figure shows two tiny 5.0-g spheres suspended from very light 1.0-m-long threads.The spheres repel each other after each one is given the same positive charge and hang at rest when θ = 4.1°.What is the charge on each sphere? (k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)

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 speed of v₀ = 2.0 × 10⁷ m/s.What is the speed of the electron as it strikes plate B? ,m_electron = 9.11 × 10^-31 kg)

An asteroid of mass 58,000 kg carrying a negative charge of Is From a second asteroid of mass Carrying a negative charge of What is the magnitude of the net force the asteroids exert upon each other,assuming we can treat them as point particles? (G = 6.67 × 10^-11 N ∙ m²/kg²,k = 1/4 πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

A solid aluminum cube rests on a wooden table in a region where a uniform external electric field is directed straight upward.What can we say concerning the charge on the top surface of the cube?

Two very small plastic balls of equal mass are released from rest.One of them carries +10 µC of excess charge and the other one carries +1µC of charge.No other charges or fields are present.Which of the following statements are true about them as they move away from each other? (There may be more than one correct choice. )

An electron and a proton are released simultaneously from rest and start moving toward each other due to their electrostatic attraction,with no other forces present.Which of the following statements are true just before they are about to collide? (There could be more than one correct choice. )

The electric field at point P due to a point charge Q a distance R away from P has magnitude E.In order to double the magnitude of the field at P,you could

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

Two tiny particles having charges of +5.00 μC and +7.00 μC are placed along the x-axis.The +5.00-µC particle is at x = 0.00 cm,and the other particle is at x = 100.00 cm.Where on the x-axis must a third charged particle be placed so that it does not experience any net electrostatic force due to the other two particles?

What is the magnitude of a the vertical electric field that will balance the weight of a plastic sphere of mass That has been charged to -3.0 nC? (k = 1/4πε₀ = 9.0 × 10⁹ N ∙ m²/C²)

The force of attraction that a -40.0 μC point charge exerts on a +108 μC point charge has magnitude 4.00 N.How far apart are these two charges? (k = 1/4πε₀ = 8.99 × 10⁹ N ∙ m²/C²)

A hydrogen nucleus,which has a charge +e,is situated to the left of a carbon nucleus,which has a charge +6e.Which statement is true?

A +5.00-μC point charge is placed at the 0.0 cm mark of a meter stick and a -4.00-μC point charge is placed at the 50.0 cm mark.At what point on a line through the ends of the meter stick is the electric field equal to zero?