The modern periodic table consists of ……………. periods.
The formulae of chloride of metal M is MCl2. The metal M belongs to ……………. group.
Corrosion can be prevented by using ……………. solution.
Find the odd one out:
(i) Voltmeter, ammeter, galvanometer, thermometer.
(ii) Loudspeaker, bar magnet, electric motor, microphone.
Reaction of iron nails with copper sulphate solution is an example of
(a) Combination reaction
(b) Decomposition reaction
(c) Displacement reaction
(d) Double displacement reaction
Dilute NaOH can be tested with
(a) red litmus paper
(b) blue litmus paper
(c) lime water
In series combination which remains constant?
(c) Both current and voltage
(d) Both are variables
An object of 10 cm is placed in front of a plane mirror. The height of image will be …………….
(a) 5 cm
(b) 15 cm
(c) 20 cm
(d) 10 cm
When a ray of light travels from air to glass slab and strikes the surface of separation at 90°, then it …………….
(a) bends towards normal
(b) bends away from normal
(c) passes unbent
(d) passes in zigzag way
What major harm is done to the human beings by air pollution?
Calculate the focal length of a corrective lens having power +2D.
Write two applications of sodium bicarbonate (baking soda).
A simple microscope is used by watch repairers. Give reason.
Draw neat and labelled diagram of pH scale.
What are the main features of Mendeleev’s periodic table?
Define ‘redox reaction’. Give one example.
Given below is a diagram showing a defect of human eye. Study it and answer the following questions.
(i) Name the defect shown in the figure.
(ii) Give reason for this defect of eye in human being.
(iii) Name the type of lens used to correct the eye defect.
What is refraction of light?
How refraction of light is related to refractive index?
Explain how spectrum is formed.
Suggest measures to avoid noise pollution in classroom.
Suggest measures in bursting fire crackers in festivals and processions.
Find the expression for the resistors connected in series and write the two characteristics of it. (Draw figure).