Home » Posts tagged 'pressure' (Page 2)

Tag Archives: pressure


Working of a microphone

How does a microphone do its work? Please explain me and can you give me answer in language Hindi I’m very thankful to you. (Shubham Agnihotri asked)

inside a microphone
Microphone is a transducer (a device which converts energy from one form to another). The microphone converts sound energy to mechanical energy and then to electrical energy.

When we speak into the mic, the vibrations of the air produced by the sound make the diaphragm of the mic vibrate. A coil attached to the diaphragm vibrates together with it. The coil is moving in a strong magnetic field produced by a permanent magnet. Whenever the magnetic flux linked with coil changes an emf is induced in it. Therefor when we speak into the mic, an emf varying similar to the pressure variations produced by our sound is produced across the coil by electromagnetic induction.

If the ends of the coil is connected to an amplifier this can be amplified and can be send to the loudspeaker. The working of the loudspeaker is just the reverse of that of the microphone. I converts the electrical signal to sound signals.

(Please use Google Translate  or Click Here to get the Hindi Version)


The pressure exerted by a given force can be decreased by increasing the area of contact.


The equation shows that pressure is inversely proportional to area.


The foundation off building is made more broader than the rest of the building so that the pressure exerted by the weight on earth can be decreased.



The shoulder straps of school bags are made wider and soft so that the pressure exerted by the heavy bags on shoulders can be reduced. You can feel the paining pressure if you try to replace the broad strap with a narrow one.




The Military tanks have a broad chain so that the pressure exerted by the heavy vehicle on ground is a minimum and it can travel even through marshy places

  • Heavy Vehicles have more tyres
  • When vehicles get struck in marshy places, wooden planks are used for the vehicle to come up.
Try to add more via comments

Thrust and Pressure: Increasing pressure by decreasing Area

Thrust is defined as the force acting normal to a surface. Pressure is the thrust acting per unit area.


The equation suggests that the pressure is inversely proportional to area. We can increase the pressure for a given force by decreasing the area. Here are some examples.

Cutting Tools

Cutting tools have sharp edges with very low area so that high pressure

can be applied by a small force. You can realise this if you try to cut a tomato with a blunt knife and try again after sharpening it.

Nails and Drawing Pins

Nails and pins have sharp ends so that it can pierce into wooden boards and walls easily by applying a small force.

In a Karate Punch


In martial arts, the normal punch is executed in such a way that only two knuckles are hitting the target so that maximum pressure can be imparted.

If the entire flat portion of the fist is used, the pressure will be very much less and the opponent will not be hurt much. Punch is only just one of the many attacks in Karate. You can analyse the various attacks and blocks with a view to find the application of pressure in it.

TRY to find out more examples where we decrease area to increase pressure.

Pressure, area and railway tracks

Why the railway track are laid on large sized wooden or iron sleepers?

(SHARANYA  posted this question)


Trains have huge masses and rails are narrow. Therefore if they are directly put on earth, they will sink down due to the extreme pressure it would exert on earth when run over by the train. So they are laid on wooden or iron sleepers of large area so that pressure on earth is reduced.
Pressure = Force /Area.

As area increases pressure decreases.

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.

What happens when we suck in water from a drinking straw that has a hole in it?And why?

Let’s first see what happens when we “suck” in water using a straw. We are actually reducing the pressure inside the  mouth. When we do not suck, the pressure on the surface of water and inside our mouth will be the same.

The Physics of Drinking with strawBut when we start to suck, the pressure inside the mouth is reduced and water is pushed into our mouth due to the greater pressure on the surface of water caused by the atmosphere.

If there is a hole, we are not able to produce a low pressure area inside our mouth by sucking in.

Dimensions and conversion of units

The height of mercury column in a barometer in a Calcutta laboratory was recorded to be 75 cm. Calculate this pressure in SI and CGS units using the following data : specific gravity is 13.6, density of water is 1000 kg/m3, g is 9.8 m/s2 at Calcutta. Pressure = hρg in usual symbols

%d bloggers like this: