Faulty relay. Or electrical problem. Lets just hope in your case its the relay. In my girlfriends Toyota corolla the relay was the one inside the drivers compartment just under the fuse box. The local autowreckers had one for $2.
In my case it was a little more complicated than this though. I replaced the relay and it was fine for a while, however the same thing happened a week later. A wire burned out from the back of the fuse box and was getting earthed somewhere. I replaced this the entire length of the wiring loom and problem fixed.
It is safe to use the bright [highbeam] headlights when there is no oncoming traffic/drivers who could be blinded by the bright light. Also, it is unsafe to use highbeams when there is fog or smoke which would reflect the light back to you, thus reducing the distance which you can see.
No, series circuits are not used in car headlights, because if one headlight were to go out the other would also, because the one light would make an incomplete circuit. Headlights are wired as parallel circuits because when one headlight goes out, the other is unaffected and stays as bright as it was before the other light went out.
Switch? both headlights?
Your headlights would come on and the light would speed ahead of the car at 186,282 miles per second.
You have a turn signal light-bulb out .
...would be dim.
Headlights have two filaments, one for dim, one for bright. From your description it appears that one of the high beam filaments is burned out. Replace the bulb.
No, they become smaller (constrict).The pupils become larger (dilate) to let in more light. The bright headlights would cause the eyes to let in less light, which means you will not be able to see anything clearly except those bright lights. You are "blinded" until your eyes adjust again, and by that time you may have veered off the road or had a collision.
The headlight fixture probably contains moisture on the inside. When the headlights are "on", the moisture clouds the light beam, diffusing the light.
If you leaned out of your car and meaured the speed of the light coming out of the headlights, you would find that it's leaving you at the speed of light.
The light beam would leave the front of them at the speed of light.
The stereo light should not go out. It should get dimmer though. They assume that if your headlights are on, it is dark outside and you don't need as much light to read the radio display as you would in bright light.