After three half-lives, what fraction of a radioactive sample has decayed

5/6

1/2

7/8

2/3

How does density of the medium affect the speed of a wave?

Sodium hydroxide (NaOH) was added to pure water (H2O). Which most likely were the pH values of the water before and after the sodium hydroxide was added to it? before = 7, after = 9 before = 7, after = 4 before = 4, after = 7 before = 9, after = 7

Which of the following will not conduct an electrical current? pure water tap water aquarium water ocean water

Why does venus have higher surface temperatures than mecury even though venus is farther from the sun?

A cylindrical insulated wire of diameter 5.0 mm is tightly wound 200 times around a cylindrical core to form a solenoid with adjacent coils touching each other. When a 0.

Why does the core of the sun contain more helium and less hydrogen than the surface of the sun?

What happens to a light ray passing through the center of a lens?

A spider crawling across a table leaps onto a magazine blocking its path. The initial velocity of the spider is 0.870 m/s at an angle of 35.0° above the table, and it lands on the magazine 0.0770s after leaving the table. Ignore air resistance.

A force of 5 N accelerates an object. The object's mass is 50 g. What is the acceleration of the object? (Formula: F=ma)

Which is a legacy of the enlightenment?