Physics Quiz: End of Nov Checkpoint

A simple pendulum oscillates with frequency f. The length of the pendulum is halved. What is the new frequency of the pendulum?

• 2f

• f

• f√2

Two isolated point masses, P of mass m and Q of mass 2m, are separated by a distance 3d. X is a point a distance d from P and 2d from Q. Which row gives the net gravitational field strength at X and the net gravitational potential at X?

• A

• B

• C

• D

A single loop of wire of resistance 10 Ω has its plane perpendicular to a changing magnetic field. The graph shows the variation with time of the magnetic flux linked through the loop of wire.

What is the maximum current in the loop of wire?

• 1.0 A

• 4.0 A

• 2.0 A

• 20 A

A resistor connects two parallel conducting rails a distance d apart. A conducting bar rolls along the rails at a constant velocity v through a uniform magnetic field of 2.0 T perpendicular to the rails as shown.

The voltage V across the resistor is measured. The graph shows the variation of V with d.

What is v?

• 6.0 m/s

• 0.33 m/s

• 12.0 m/s

• 3.0 m/s

A student states three facts about the time constant of a resistor-capacitor series circuit.

I.   It is the time required for the capacitor to be charged through the resistor to a voltage of 0.632 V from an initial value of zero, where V is the voltage of the source.

II.  It is the time required for the capacitor to be discharged through the resistor to a voltage of 0.632 V, where V is the initial voltage of the capacitor.

III. It is the product of the resistance of the resistor and the capacitance of the capacitor.

Which statements are correct?

• I and II only

• I and III only

• II and III only

• I, II and III

The nucleus of the isotope hydrogen-2 has a radius R and a density ρ. Which row shows the approximate radius and density of a nucleus of oxygen-16?

• A

• B

• C

• D

A direct current I in a lamp dissipates power P. What root mean square (rms) value of an alternating current dissipates average power P through the same lamp?

• I

• I√2

• 0.5I

A rectangular flat coil moves at constant speed through a uniform magnetic field. The direction of the field is into the plane of the paper. Which graph shows the variation with time t, of the induced emf ε in the coil as it moves from P to Q?

• Graph C

• Graph D

• Graph B

• Graph A

The graph shows the power dissipated in a resistor of 100 Ω when connected to an alternating current (ac) power supply of root mean square voltage (V_rms) 60 V. What are the frequency of the ac power supply and the average power dissipated in the resistor?

• A

• B

• C

• D