Electrical Charges Questions - Physics

A 5cm radius isolated conducting sphere is charges so its potential is +100V, relative to the potential far away. The charge density on its surface is:

+1.8e-8 C/m2

A battery with an emf of 12 V and an internal resistance of 1 ohm is used to charge a battery with an emf of 10 V and an internal resistance of 1 ohm. The current in the circuit is:

1 A

Four circuits have the form shown. The capacitor is initially uncharged and the switch S is open. Rank according to the time after S is close to reach half their final charges, least to greatest.

1, 3, 2, 4

A charged capacitor stores 10 C at 40 V. Its stored energy is:

200J

Two identical capacitors, each with C are connected in parallel and the combination is connected in series to a third identical capacitor. The equivalent capacitance of this arrangement is:

2C/3

A conducting sphere has charge Q and electric potential V, relative to the potential far away. If the charge is doubled the potential is:

2V

Two conducting spheres are far apart. The smaller sphere carries a total charge of 6e-8C. The larger sphere has a 2r radius and is neutral. After being connected by a conducting wire what are the charges?

2e-8C: smaller 4e-8C: larger

Two conductors are made of the same material and have the same length. Conductor A is a solid wire of diameter 1m. Conductor B is a hollow tube of inside diameter 1m and outside diameter 2m. The ratio of their resistance, RA/RB is:

3

A 200 N/C electric field is in the positive x direction. The force on an electron in this field is:

3.2e-17 N in the negative x direction

An electron goes from one equipotential surface to another alone one of the four paths shown below. Rank according to work done least to greatest

4 & 2, 3, 1

The plate areas and plate separations of five parallel plate are: 1: A d 2: 2A 2d 3: 2A, d/2 4: A/2, 2d 5: A d/2 Rank according to capacities, least to greatest.

4, 1 & 2, 5, 3

An isolated charged point particle produces an electric field with magnitude E at a point 2m away. At 1m from the particle the magnitude of the field is:

4E

A cylindrical copper rod has resistance R. It is reformed to twice its original length with no change in volume. Its new resistance is:

4R

Resistances of 2 ohm, 4 ohm, 6ohm and a 24-V emf device are all in series. The potential difference across the 2 ohm resistor is:

4V

An isolated charged particle produces an electric field with magnitude E at a point 2m away. At a point which the magnitude is E/4 is:

4m away from the charge

To charge an electroscope by induction:

Bring a charged rod near Ground electroscope Remove ground Remove charged Rod

+Q is uniformly distributed on the upper half of a semicircular rod and -Q is on the lower half. What is the direction of the electric field point P in the center of the semicircle?

Downwards

Two particles, X and Y are 4m apart. X has a charge of 2Q and Y has a charge of Q. The force on X to that on Y:

Has the same magnitude of the force of Y on X

In the diagrams, all light bulbs are identical and all emf devices are identical. In which circuit will the bulbs be dimmest?

IV

Two uncharged metal sphere, L & M are in contact. A negatively charged rod is brought close to L, but not touching. The two spheres are slightly separated and the rod is then withdrawn. As a result:

L is positive and M is negative

A battery is used to charge a series combination of two identical capacitors. If the potential diference across the battery terminals is V and total charge Q flows through the battery during the charging process then the charge on the positive plate of each capacitor and the potential difference across each capacitor are:

Q and V/2

A battery is used to charge a PARALLEL combination of two identical capacitors. If the potential diference across the battery terminals is V and total charge Q flows through the battery during the charging process then the charge on the positive plate of each capacitor and the potential difference across each capacitor are:

Q/2 and V

An electron traveling north enter a region where the electric field is uniform and points west. The electron:

Veers east

A particle with charge 5.5*10-8 is fixed at origin. The change in PE of 2 particle system is:

c) 6e-5 J

The equipotential surfaces associates with a charged point particle are:

concentric spheres centered at the particle

Pulling the plates of an isolated charged capacitor apart:

increases the potential difference

The directions of force for an e, e, p are, starting for e1

left, right, left

In separate experiments, four difference particles each start from far away this the same speed and impinge directly on a gold nucleus. p1: m, q p2: 2m, 2q p3: 2m, q/2 p4: m/2, 2q Rank particles according to distance, from smallest to largest

p3, p1 & p2, p4

An electron traveling north enters a region where the electric field is uniform and points north. The electron:

slows down

Capacitors C1 and C2 are connected in series and a potential difference is applied to the combination. If the capacitor that is equivalent to the combination has the same potential difference, then the charge of the equivalent capacitor is the same as:

the charge on C1

Two wires made of the same material have the same length but difference diameters. They are connected in series to a battery. The quantity that is the same for the wires is:

the current

When the electric field lined are going towards z and away from y

the electric field is not zero anywhere.

When -Q is top charge and +Q is bottom charge with a P bisector, the electric field points

upwards