Thermometer should be held from its bulb.

Two lenses of power +10 D and -5 D are placed in contact. Where should an object be held from the lens,so as to obtain a virtual image of magnification 2?

Why no electron is emitted from a wooden table when light from a bulb falls on it?

What happens to the intensity of light from a bulb if the distance from the bulb is doubled? As a laser beam travels across the length of a room, its intensity essentially remains constant. What geometrical characterstics of LASER beam is responsible for the constant intensity which is missing in the case of light from the bulb.

State similarities and differences between the laboratory thermometer and the clinical thermometer.

________is used in the clinical thermometer and laboratory thermometer to measure the temperature.