1. An object of mass $m$ and charge $q$ is dropped vertically between two parallel plates, $K$ and $L$. A magnetic field $B$ can be created perpendicular to the plane of the paper. The electric field between plates is $E$.

Which of the following is correct about the magnitude of magnetic and electric fields when the object falls vertically at a constant velocity v?

2. A beam of electrons enters a uniform electric field, as shown.

What effect does this field have on the horizontal and vertical components of the electrons' velocity?

3. A charge of $X$ and a charge of $20nC$ are held at a fixed distance.

A point where the electric field is zero can only be found in region 1. Which of the following statements is true about the charge on $X$?

4. A satellite $X$ is in a circular orbit of radius $R$ with a period $T$ around Earth.

What will be the orbital radius of satellite Y, travelling in a circular orbit with a period of 8$T$ around Earth?

5. Two stars of equal mass $M$ are shown in the diagram, distance $d$ apart. A planet is equidistant from the two stars, with distance d/2 across the midpoint of the line joining the stars as shown.

What is the resultant gravitational field strength at the position of the planet due to the two stars?

6. In the following diagram, the size of the charges is small compared to the distance R.

What is the direction of the force on the charge in the center?

7. A source of radiation is near a magnetic field that is directed into the page. A sheet of paper is placed in the path of the radiation before it enters the magnetic field.

The gamma radiation is not deflected when entering the magnetic field. Which of the following is correct about the other type of radiation that penetrates the paper sheet and the direction of its deflected path in the magnetic field?

8. The centers of three masses lie on the same line. The centers of the masses are separated as shown.

The net gravitational force on m2 is zero when the value of $d$ is one third of $x$. What is the ratio m1/m3?

9. Two charges, separated by a large distance, are shown below, along with the electric field lines around each charge.

Which of the following statements is correct?

• I.  The charge $q$ is positive.
• II.  The charge $q$ is equal in magnitude to $+Q$.
• III.  The electric field magnitude near the charge $q$ is greater than the magnitude of the field near the charge $+Q$.

10. The gravitational field strength on the surface of the moon is gE/6. Two objects of different masses $m$ and $2m$ are released with zero speed on the moon from heights of $h$ and $2h$, respectively, where $h$ is small compared to the radius of the moon.

What are the magnitudes of the accelerations of these objects right after release?

11. A current-carrying wire is at right angles to a uniform magnetic field. The magnetic force per unit length on the wire is F/L. The length of the wire, the magnitude of the magnetic field strength, and the current of the wire are all doubled. Which of the following is the magnetic force per unit length on the wire after these changes?

12. A positive and a negative charge of equal magnitude are located on the same horizontal line.

What is the direction of the net electric field at the point marked X, equidistant from the two charges?

13. Satellite $A$ of mass $M$ orbits a planet with an orbital speed $v$ and orbital radius $R$. Another satellite $B$ with mass $3M$ orbits the same planet with the same orbital speed.

14. Which of the following is correct about the gravitational field strength at a point near a planet?

15. A hydrogen nucleus is held stationary in a uniform vertical electric field, represented by the arrows. Which of the paths shown would require the largest work to be done on the hydrogen nucleus?

16. An astronaut in a space station orbiting the earth experiences weightlessness.

The following are three statements about the astronaut and the space station:

• I.  The astronaut experiences no gravitational force.
• II.  The centripetal acceleration of the space station is equivalent to the gravitational field strength at that location
• III.  Both the astronaut and the space station have the same acceleration.

Which of these statements is correct?

17. A satellite of mass $m$ is in an orbit at a height $h$ from the surface of a planet of mass $M$. The centripetal force acting on the satellite is $F$ and the linear speed is $v$.

What is the new centripetal force and linear orbital speed when it is moved to a new orbit at $2h$ from the surface of the planet?

18. Two objects A and B are separated by a distance $r$. The mass of A is much larger than that of B.

Which of the following is correct about magnitude and direction of the gravitational force exerted by A on B compared to that exerted by B on A?

19. An electron enters a region of magnetic field with a velocity as shown in the diagram. The path followed by the electron is shown by the dotted line. What is the direction of the magnetic field in this region?

20. Two sections of current-carrying wires, $X$ and $Y$, that lie in the plane of the paper, are shown below. The arrow in wire $X$ shows the direction of conventional current. Which response gives possible directions of current in wire $Y$ and electromagnetic force acting on $Y$?

21. Satellites $A$ and $B$ orbit the same planet of mass $M$. Satellite $A$ has a mass of $3m$ and it is located at a height of $R$ from the surface of the planet. Satellite $B$ has a mass of $m$ and it is located at a height of 2$R$ from the surface of the planet.

What is the ratio of the centripetal force acting on $A$ to the centripetal force acting on $B$?

22. A charged particle is moving horizontally when it enters an electric field between two parallel plates. The path followed by the particle when it passes through the plates is shown. Assume gravitational effects to be negligible.

Which statements are correct about the charged particle?

• I. The particle is positively charged.
• II. A magnetic field in a direction into the page could cause the charged particles to move horizontally without deflection.
• III. A magnetic field in a direction out of the page could cause the charged particles to move horizontally without deflection.

23. Four fixed charged point particles are at the vertices of a rectangle. Which arrow represents the net electric field at the center of the rectangle?

24. Which of the following correctly lists the fundamental forces in decreasing order of strength?

25. Which of the following graphs shows the variation of the gravitational field strength of a planet with distance $r$ from the surface of a planet?

A.			B.
C.			D.