Loaded test-tube placed in pure milk sinks to a certain mark (M). Now some water is mixed with the milk. Will the test tube sink more or less? Explain.

Four test tubed marked I,II,III and IV were taken 20 ml of Al_2(SO_4)_3 solution in water was poured in each of the test tube I, an iron nails was put in test tube II, copper turnings were put in test tube III and a clean aluminium strip was placed in test tube IV. No change was observed in any four any in the test tubes. the correct inference drawn is

An empty test tube is placed slanting in the water and viewed from above, what will you observe?

Some reduced iron filings and powdered roll sulphur are well mixed and heated in a test tube. Describe all what you observe.

The blue colour of crystals of a substance changed on heating in a closed test tube but the colour was regained after some time on cooling. Name the substance and write its chemical formula. Explain the phenomenon involved.

Suppose that a radio tube insrted into a certain type of set has a probability0.2 of functioning more than 500 hours. If we test 4 tubes, what is the probability that exactly three of these function for more than 500 hours, .