why the blades are more curved for table fan than ceiling fan?

A ceiling fan has blades of about 5 times larger in size, i.e. it sweeps around 25 times more area/air than a table fan which implies around 25 times higher drag i.e will require 25 times more powerful motor to act with same pitched blades
but the motors for both of them is comparable, hence the pitch is lower, while for the table fan(which is designed for portability & can't have long blades) with comparable power motor, can afford more curved blades, & finally be able to sweep larger maximum amount of air.

Why do normal fans have 3 blades

1.More blades implies more power required to push through air & due to limited power motor, will effect directly on the speed of fan, hence finally leading to lower air flow in the room.

2.Excessively larger number of blades are also useless as, if a fan is able to sweep the air in its particular area with just 3 wings, the power implied to move the 4th gets wasted.

3. single & double blades also leads to imbalance, also very high velocities are required to work with this kind of fans.

Carbon Nanotubes

So we having a presentation on CNT's tomorrow. Me, Saurabh & Sandeep.

What a great thing is it yaar..
Toughest, lightest, most conductive, so small, strongest field emitter...and yeah costliest :P

• Make a cable, hang on a man...no you won't see the cable.
• Play out your favourite tracks from a sheet thinner than paper, or say from your shirt"A singing shirt"
• Have HD TV's in your bedroom, with energy costs less than the LCD's & plasma
• Drug Boats: Deliver medicines where you want them to, eliminate cancer.
• Wanna be spider-man have a CNT suit...climb up vertical walls

Yes. you can do all this, that's real...welcome to the world of CNT's