Why is sodium light used in Newton's ring experiment?
In newtons ring experiment a plano convex lens is placed over a glass plate and air film is enlosed between them. The light incident in it is partially reflected from the upper and lower surface of glass plate. These two reflected lights are superimposed to form newtons ring. This is possible only when the light has a single wavelength. So sodium light is used as it has a single wavelength.
Chemistry: Calculate the mass of each cylinder.?
A thief uses a can of sand to replace a solid gold cylinder that sits on a weight-sensitive, alarmed pedestal. The can of sand and the gold cylinder have exactly the same dimensions (length = 20 cm and radius = 4.5 cm ). Calculate the mass of each cylinder (ignore the mass of the can itself). (density of gold = 19.3 g/cm^3 , density of sand = 3.00 g/cm^3 ) Did the thief set off the alarm?
If we drop a metal ball and a wooden ball from same height at the same time, then which ball will reach the ground first?
The answer to this question will vary based on the situation. Let me elaborate it situation wiseExperiment conducted in total vacuum : In this case both the metal ball and the wooden ball will hit the ground at the same time!!!, irrespective of their shape, weights and sizes. The time required to hit the ground, depends on the acceleration of the object, which in this case if ‘g’ (gravity) acting same on both the objects.Experiment conducted in atmosphere: Here we have air which fills in the atmosphere. Air being a fluid, would enable two things - Buoyancy and air-resistance. In this case, the outcome of the experiment would depend on the following parametersShape of the balls - The ball with a more aerodynamic shape would touch the ground first. As it would have lesser air-resistance, thus the resultant acceleration acting on it would be more.Volume of the ball - The ball having lesser volume will hit the ground first. Since air is a fluid, buoyancy would act on it. Buoyancy is directly proportional to the volume ( ρ x V x g).Weight of the ball - The ball having higher weight will hit the ground first. This is because of the resistive force would have lesser impact on the net acceleration (g-a).In theory, as per Galileo, the answer is indeed straight forward! But life is not that straight forward.I hope this helps!
Buoyancy: Is the buoyant force on a lead object greater than, less than or equal to the buoyant force on an iron object of the same volume?
The question has already been answered in a very nice way above. Let me add a couple of more points to clarify the doubts that normally come to the mind of a beginner.The magnitude of the Buoyant force ([math]F[/math]) is given by the formula :[math]F = ρ.g.V[/math]Where [math]ρ[/math] is the density of the fluid (not the density of the object), [math]g[/math] is the acceleration due to gravity and [math]V[/math] is the volume of the fluid displaced. If the object is fully submerged, you may take volume [math]V[/math] as volume of the object too as they are equal in this case.Conclusion 1: If they are submerged in the same fluid (with same density [math]ρ[/math]) and at the (same) places where the acceleration due to gravity [math]g[/math] is the same, then the two balls with equal volume, [math]V[/math] will have the same Buoyant force acting on them.Conclusion 2: If you drop them in a bucket of water, their behavior would surely be different. The iron would sink, and the lead would sink more rapidly. This is so because the block of lead would have heavier mass ([math]m[/math]) owing to its heavier density. Thus the downwards force acting on it, i.e. its weight ([math]w[/math]=[math]m.g[/math]) would be more. But the buoyant force on each is the same.Additional Point 1: If you take a cork of the same volume, it would also experience the same buoyant force. But, it would bob up and float as the buoyant force here would be greater than the weight of the cork (owing to a lesser density of the cork, thereby lesser mass, thus a lesser weight).Additional point 2: From the equation [math]F = ρ.g.V[/math], it is clear that the buoyant force doesn’t depend on the mass of the immersed, or the density of the object immersed or the nature of the object immersed.
If you dropped a piece of ice at 0 °C into water of 0 °C, what would happen to ice?
Observations of a tour skaterNordic Tour skatingWater freezing to ice is a difficult process. If you look at a sea when the air temperature is below 0 the sea do not freeze instantly. The freezing always starts at an edge were water is connected to a solid state object. Some water molecules are than, by the random laws of quatum physics connecting to the existing ice which will make the ice grow outwards in the lake. The ice will grow until it covers the entire lake. The ice have than laid itself on the lake (is that an English expression?). The lake will appear as a safe place for walking, and it is, except at some points in the middle of the lake were the ice will be too thin to carry a man. Watch out!To avoid a cold bath you should not enter the ice directly after the ice have laid iiself over thr lake. What a few days. And heres comes the strange thing:Ice will freeze above 0 degrees.When the ice is all over the lake the ice will continue to grow even when the temperature is above 0. Actually it will not start smelting until the air temperature is above 5 degrees.The explanation must be that when the temperature is below 5 degrees water molecules are more likely to get stucked on ice rather than to get loose from ice. As energy is consumed when ice is melting and produced when ice is freezing, this means that a lake that is freezing do produce heat.The 0 degrees scenarioIn the suggested scenario the ice will grow and produce heat. The water close to the ice will be warm. Mayby up to 1 degree. The warm water will sink to the bottom. The water in the cup will then have a gradient with the warmest water in the bottom and a cover of ice.The final state will be an even cover of ice and and a somewhat warmer water in the bottom