Which of the following combinations of elements is most likely to produce covalent bonds?

a. hydrogen & helium

b. sodium & magnesium

c. fluorine & bromine

d. aluminum & bromine

Light cannot be linearly polarized by: transmission reflection diffraction diffraction

Which of the following have circular orbits? moons comets planets none of the above

A gas-powered lawnmower is rated at 98 db. how many times more intense is the sound of this mower than that of an electric-powered mower rated at 70 db?

the mechanical advantage of an automobiles wheel and axle is 0.0893 if the wheel is output force is 2220n what is the input force that turns the axle

When determining whether a chemical reaction has taken place, you observe and look for several indicators. Which would be considered an indication that a chemical reaction or chemical change has taken place? A) Solid melts. B) Heat is given off.

A gate in an irrigation canal is constructed in the form of a trapezoid 2 m wide at the bottom, 38 m wide at the top, and 2 m high. It is placed vertically in the canal so that the water just covers the gate.

A machine with a mechanical advantage of 10 is used to produce an output force of 250 newtons. What input force is applied to this machine

Why do you float in space

How does physical change affect the identity of a substance

A scientist pours grape juice on three identical white shirts He then uses three different cleaning products on the shirts and measures how clean they get what is the independent variable in this experiment