Yes, or course. But the light has to be pretty intense for you to feel it. Light exerts radiation pressure, but this effect is very small. More significantly, light delivers energy.

Or, E = [M] × [L1 T-1]2 = M1 L2 T-2. Therefore, energy is dimensionally represented as M1 L2 T-2.

While most experiments have found that light exerts a pulling pressure, in a new paper physicists have, for the first time, found evidence that light exerts a pushing pressure.

Yes, light or any other form of electromagnetic radiation can exert a force on an object, it is called Radiation pressure. Light is made up of photons and when these photons collide with the surface of an object they transfer momentum. This is similar to a tennis ball hitting an object.

Light carries momentum that can push on an object, but it can also move an object through thermal forces. The air molecules on the hot side heat up, and their collisions with the object deliver more momentum than those on the colder side, producing motion, as in the rotation of a radiometer (light mill).

So when you turn the light switch on, you are effectively turning on a circuit, which has a light bulb (or several of them). What happens is that the current in the circuit then interacts with atoms in the filament and it causes them to heat up.

If the bulb flickers on and off, it usually means that the switch contacts are getting bad. By far the most common problem is a loose wire connection at the switch itself, which is subject to constant on-off usage. Less commonly, a light bulb socket may go bad. If so, you will need to replace the socket.

Just to recap, a “phantom voltage” is where a wire from a switch to a light or outlet runs next to a permanently live wire, when the switch is off, the AC voltage in the other wire can induce a voltage in the switched-off wire.

The live wire is the most dangerous one, since it is at 230 V. Even if a circuit is switched off (i.e. the switch is open), the live wire can still be dangerous. If you touch it, you may complete a circuit between the live wire and the earth (because you’ll be standing on the floor), so you get a shock.

It’s simple. Since switches have no neutrals, you’re measuring voltage across the switch. The wire from the switch to the lamp is not a neutral, but connected to neutral via the light – a resistor, and that explains why you’re getting only 50 volts.

Measuring for voltage across a closed switch (ON) will give you zero volts. Measuring across an open switch (OFF) SHOULD give you 120 VAC.

In North America it is 110–120 volts. European uses appliances of a greater voltage of around 220 volts. Both are alternating current. Generally a light circuit will carry no more than 20 amps.