Supercooling – Instant Ice

Instant Ice This is made possible by supercooling. Supercooling is the process of lowering the temperature of a liquid or gas below its freezing point WITHOUT it becoming a solid. The moment you disturb the supercooled water(below 0 degrees celcius), the water will freeze instantly and will even increase in temperature to 0 degrees celcius. Want to try this at …

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Questions for Oscillations (JC) Set 1

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 …

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Questions for Current (JC) Set 2

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 …

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Questions for Superposition (JC) Set 1

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 …

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Questions for Thermal Physics (JC) Set 1

Which of the following statements about the thermodynamic scale is not correct? It is also known as the Kelvin scale. It is a shifted scale from the Celsius scale by a value of 273.16. One degree change in the thermodynamic scale is equivalent to one degree change in the Celsius scale. The zero value of the thermodynamic scale represents the …

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Questions for Electric Field (JC) Set 1

In discussing electric fields, the terms ‘electric field strength’, ‘electric potential’ and ‘potential gradient’ are used. Which statement about these terms is correct? Electric potential and potential gradient are both scalar quantities. Electric field strength at a point is the work done in bringing unit positive charge from infinity to the point. The potential gradient at a point is numerically …

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