Physics
Read the excerpt from a story and answer the questions that follow:
On stage, a soft iron box sits atop a hidden copper coiled platform, conductive to electricity. I summoned a man who fancied himself a modern-day Hercules onto the stage and challenged him to lift the iron box. With ease, he lifted it up. Then, with a wave of my magic wand and a hidden switch activated, I said, "I'm going to take away your strength." When I asked him to lift the box again, he struggled, unable to budge it.
(a) Explain the secret behind the magic.
(b) If you are asked to design the same magic in your science lab, give the necessary circuit diagram.
(c) Give any one device that works on the same principle.
Related Questions
Which one of the switches, S1, S2 or S3, should be opened so that:
(a) total resistance is equal to 4 ohms.
(b) the total resistance is equal 3 ohms.
(c) the current through 4 ohms is 3⁄5th of the total current.
In the given diagram, X represents a conductor carrying current into the plane of the paper and kept in a magnetic field. N & S represent the poles of a magnet and concentric circles of the magnetic field produced by the conductor.
(a) State the direction of the force experienced by the conductor.
(b) Explain the cause of the above-said force.
(c) Name the law used to determine the direction of the force in the conductor.
Study the diagram and answer the following:
(a) Arrange the following pendulums according to their natural frequencies (use < > =).
(b) If Pendulum Z is initiated into oscillation, which pendulum among the others will exhibit the highest amplitude of vibration?
(c) Give reasons for your answer.
In the physics laboratory, various blocks of materials labelled A and B, each with masses ranging from 10 grams to 50 grams, are utilised to determine their respective heat capacities. Subsequently, a graph is plotted to depict the relationship between the heat capacity and the mass of the materials, as shown.
(a) Plot a graph illustrating the relationship between the mass and specific heat capacity of materials A and B.
(b) Which material is a relatively better conductor?