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Flow of air?

I’m working on a science project now and I have a doubt,Consider two places(A and B) with a vast temperature difference connected by a insulated pipe,would air flow through the pipe from A to B?lets say A is up in the mountains and B is in the plains,air flows from a cold place to a hot place,doesn’t it?If it does flow, I would like to know how to calculate it’s pressure.If it doesn’t flow,I would like to know the reason for that as well.

Why can’t we see through opaque objects?

Why can’t we see through opaque objects? What is the reason?

(Kavya asked)

Answer: When light falls on an object, a part of it is absorbed, another part transmitted and the rest reflected. Surfaces have different abilities for these. Substances which do not transmit any light are opaque.

Why does magnet attract only some of the materials like iron why not plastic ? What is the absolute reason behind it?

Why does magnet attract only some of the materials like iron why not plastic ? What is the absolute reason behind it? (Ankit Gururani posted in facebook)

Answer:

The answer cannot be limited to a quick reply.

The cause of magnetism is revolution of electrons. A revolving electron acts like a tiny magnet just like a current carrying coil does. If the magnetic moments of all the electrons nullify the effect of each other, it is non magnetic else it is a magnetic substance.

A magnetic substance consists of atoms or molecules having a net magnetic dipole moment. When an external magnetic field is applied or another magnet is brought near, the magnetic dipole moments get aligned and this results in the attraction of the magnetic substance by the magnet.

When the magnetic substance have their dipole moments aligned, it is said to be magnetised.

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you are given two nichrome wire of same length and different thickness Which wire will get heated first Give reason.?

You are given two nichrome wire of same length and different thickness Which wire will get heated first Give reason.? Asked Merlin Mary Mathew

Answer:

If the wires are connected one by one to a source, (or connected in parallel to the same source) the one having less resistance (Greater thickness) will get heated up first. This is because, for constant voltage, Heat dissipated is inversely proportional to resistance.

If both are connected in series to a power supply, the one with less thickness will get heated up as same current is flowing through both and then heat generated is directly proportional to resistance.

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