A student observed a plant cell through a microscope and made an accurate drawing of the cell. If her drawing was 80 mm in diameter and had a magnification of ×2000, what was the real diameter of the cell?

The only common gas that turns moist red litmus paper blue is:

Which one of the following is NOT a vector quantity?

Which of the following are natural barriers to infection?
Ⅰ tears
Ⅱ skin
Ⅲ stomach acid
Ⅳ mucus

If a reaction takes 50 seconds at 25 ℃, then at 50 ℃ the time for the reaction in seconds is likely to be about:

In a titration the long tube with a volume scale is a:

The standard atom used for mass calculations is:

In electrolysing a solution of copper sulphate using copper electrodes, the anode:

Which of the following sets has a finite number of members?

The only one of the following which is NOT a change of state is:

The number of electrons in a full electron shell is:

The halogens are found in:

Which of the following is a subset of {b, c, d}?

The halogen used to make bleach is called:

None of these solutions in water conducts electricity EXCEPT for:

When an acid neutralises an alkali the pH is likely to be:

A detector close to a sample of radioactive material records 76 counts per second (cps). Precisely 2 days later the count rate has fallen to 22 cps.The count rate due to background radiation, taken immediately before and after the experiment, averaged 4 cps. The half-life of the material is:

A reaction that gives out heat is said to be:

Any solution with a pH below 7 must be:

The two main protein groups are globular and: