Do You Know
Questions & Answers on General Knowledge.
How does a smoke alarm work?
The most common type of smoke detector uses a tiny amount of a radioactive element called americium to inject electric charges into the air. In the absence of smoke, these electric charges attach themselves to individual air molecules and the resulting ions (electrically charged molecules) move rather easily through the air. However, if there is smoke present in the air, the electric charges attached themselves to the smoke particles and the resulting charged smoke particles don't move easily through the air. The smoke detector measures how easily the charged items it produces move through the air. If these items move easily, then the air is clean. However if they don't move easily, the air contains smoke and the detector signals danger.
Why is it so difficult for women to join prestigious British golf clubs?
With a pulley of 5 strings, why is each string experiencing 10 N of force and not 2 N apiece (when you pull on the string with 10 N of force)?
Could you give me the formula for figuring the wavelength of an ultrasound wave?
Which is the longest mountain range in South America?
Why do we say that someone looking for trouble has a “chip on his shoulder”?
Why is there more gravity acting on larger, more massive objects?
When light hits an object, how do we recognize the color?
Does an MRI work in the same way as a copier (or puts you in a magnetic field and copies an image of your body)?
If you use a heavier racket, will you be able to hit a badminton birdie farther?
What is a seed drill?
How does fuzz on a tennis ball make it fly faster? It seems counterintuitive to me.
When was the first post office in the United States established and how did the system grow?
If airplane cabins are pressurized to provide adequate oxygen for the passengers to breathe, what provides this compressed air?
How do photocells work?
Is air a fluid or a gas or both?
When did men start shaving every morning?
What colour is light?
Why is extortion money called “blackmail”?
Why does everyone touch wine glasses before drinking at a dinner party?
How hot is a match when it is ignited? Is the initial point of combustion hotter than when it is just burning?
How does a roller coaster work?
Do all pythons have red eyes?
How does a paper airplane fly?
How many dwarf planets are there in the solar system?
What did the stegosaurus use the plates on its back for?
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