What is the symbol for the element Actinium?

a. Ac
b. Tl
c. B
d. Md
e. He


a

Physics & Space Science

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A point charge Q is placed on the x axis at the origin. An identical point charge is placed on the x axis at x = -1.0 m and another at x = +1.0 m. If Q = 40 mC, what is the magnitude of the electrostatic force on the charge at x = +1.0 m?

a. 29 N b. 14 N c. 11 N d. 18 N e. 7.0 N

Physics & Space Science

What are the "rungs" of a DNA spiral made up of?

a. RNA b. four chemical bases arranged in pairs c. enzymes d. ribosomes e. proteins

Physics & Space Science

Which of the following is a difference between low-mass stars and medium-mass stars?

A) Unlike medium-mass stars, low-mass stars can ignite hydrogen and helium. B) Unlike medium-mass stars, low-mass stars develop an inert helium core surrounded by unprocessed hydrogen. C) Unlike medium-mass stars, low-mass stars are not completely convective. D) Unlike medium-mass stars, low-mass stars cannot become giant stars.

Physics & Space Science

It takes ________ years for the sun to progress through one sunspot cycle from a maximum area covered with sunspots, to a minimum, and back to a maximum. Refer to the graph above

A) about 1 year B) about 110 years C) about 10 years D) This figure cannot be used to answer this question.

Physics & Space Science