IB HL Physics Poorly Answered Questions 1

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Below are 11 questions encountered in IB HL Physics that are poorly answered. Can you do them?

  1. The current in the primary coil of an ideal transformer having 200 turns in the primary coil and 120 in the secondary coil is a sine function of period 2.0 s and phase angle 𝜋/2. Draw the current-time graph for the secondary coil from t=0 to t=2.0 s.
  2. Photoelectrons are being emitted from a metal surface. Light of the same intensity but higher frequency now shines on the metal. Does the rate of photoelectron emission stay the same, decrease or increase?
  3. The initial activity of a radioactive substance is known. The half-life is required to be found. Can the half-life be found if the mass remaining at a later time is measured?
  4. A coil spins at a constant rate of 2.0 rads-1 in a uniform magnetic field. The average electrical power due to ohmic heating in the coil is 40 W. Draw a graph showing the electrical power versus time for one complete rotation of the coil. Initially the plane of the coil is perpendicular to the magnetic field lines.
  5. A stationary vertical cylinder of cross sectional area A and length L contains N particles of an ideal gas at a kelvin temperature T and pressure P. The mass of the gas is M. What is the force exerted by the gas on the base of the cylinder?
  6. Two stars are observed through a telescope. The images are just resolved when a yellow filter is placed over the telescope. Are separate images seen when the yellow filter is replaced by a red filter? Why?
  7. Two parallel wires of lengths 1.0 m and 2.0 m carry currents of 2.0 A and 1.0 A in opposite directions in a vacuum respectively. If the magnitude of the electromagnetic force acting on the shorter wire is 2.0 mN determine the magnitude and direction of the electromagnetic force acting on the longer wire.
  8. The air column in a pipe is vibrating in its second harmonic. Are the nodes always at the centre of a compression?
  9. A single electron atom has 4 energy levels. In terms of energy values, the lower two energy levels are close together and the top two levels are very close together. Draw the emission spectrum of this atom labelling the longest wavelength transition.
  10. A weight W is suspended from the roof by two strings of equal length. When one of the strings is suddenly cut the initial tension in the remaining string (a) always increases (b) always decreases (c) always stays the same (d) can stay the same
  11. One kilogram is now defined in terms of which of the following natural constants? e, c, h, kB, fCs, NA, KCd