A horizontal bar is rotating at an angular velocity v about a vertical axis through its centre in a region of constant magnetic field B directed parallel to its vertical axis. What is the e.m.f. between the two ends of the bar? It is zero. It is proportional to the product Bv. It is proportional to the product Bv2. It …
When a p-n junction is under reverse bias mode, the width of the depletion region will be increased. Which of the following statements is true? The applied voltage moves the electrons from n-type region to p-type region. The applied voltage moves the holes from p-type region to n-type region. The applied voltage drives the electrons towards n-type region. The applied …
Which of the following scenarios about the de Broglie wavelength of an object is not possible? A 100 m sprinter has a wavelength of about 10-36 m. A stationary electron has wavelength of infinite length. An elephant with an associated wavelength equals zero. A Sumo wrestler has wavelength smaller than a child when both moves with the same speed. In …
a) (i) The First Law of Thermodynamics is in agreement with the Principle of Conservation of Energy. Give a word equation stating the First Law of Thermodynamics. (ii) A student suggests that when heat is supplied to a system, the temperature will always increase. Give an example to show when the statement is not true. b) When a system is …
A mass attached to the lower end of a vertical spring is performing simple harmonic motion. Which of the following statements is correct? When the kinetic energy of the oscillator is equal to its potential energy, the oscillator is neither at the rest position nor at its maximum displacement position. The kinetic energy of the oscillator is a maximum when …
A row of 15 decorative lights, connected in series, is connected to a power supply. When the supply is switched on, the lights do not work. The owner uses a voltmeter to test the circuit. When the voltmeter is connected across the third bulb in the row of lights, a reading of zero is obtained. Which of the following cannot …
Sound from a small loudspeaker L reaches a point X by two paths which differ in length by 1.8m. When the frequency of the sound is gradually increased, the resultant intensity at X reaches a maxima when the frequency is 1000 Hz. Given the velocity of sound is 360 m s-1, at what next higher frequency will a maximum be …