A student built an electric circuit that consists of an ideal battery, a voltmeter with resistance RV, an ammeter with resistance RA and a resistor R. She connected all elements in the circuit as shown in Fig. (1). The voltmeter showed a reading of 1V and the ammeter showed a current of 1A. Then, another student switched between the voltmeter and ammeter Fig. (2). As a result, the voltmeter showed the reading of 2V and the ammeter showed the current of 0.5A. What is the resistance of the resistor?
Three batteries have their negative terminals connected together.
Find the voltage read by an ideal voltmeter.
A rod of length L carries a charge Q uniformly distributed along its length.
Find the electrical field at point P on the axis of the rod, a distance a away from the end of the rod.
A conducting rod of length l, mass m, and resistance R is suspended by two vertical conducting wires of lengths d each. The circuit consists of a battery ε, the horizontal fixed wires, two parallel vertical wires , and the conducting rod. All conducting wires have negligible resistance and mass. There is a conducting long cable. The cable is below the rod and at a distance x.
A ball of mass 0.2 kg is attached to a massless string 1 m long and swung so that it travels in a horizontal circle of radius 0.5 m.
a) Draw a free-body diagram.
b) Find the force of tension in the string as the ball swings in a horizontal circle.
c) Find the period of the ball’s motion.
The quantum tunneling phenomenon is negligible in the classical mechanics.
Show that the tunneling probability equals 0 for an object of mass 0.007 kg moving at a speed of 0.1 m/s against a solid obstacle of height 0.05 m and width 0.01 m.