Is sharpening a pencil a physical change or chemical change

What type of light does this light bulb produce most (i.e. at what wavelength does the spectrum have maximum intensity)?

The table below shows the acceleration of gravity on different bodies in the solar system. on which body would a 10 kg lamp has the most gravitational potential energy when lifted to a height of 2 m? a. earth b. mars c. neptune d. uranus

An isotope undergoes radioactive decay by emitting radiation that has a –1 charge. what other characteristic does the radiation have?