The metallic constituents of hard water are
Calcium, magnesium and iron
Magnesium, Calcium and tin
Magnesium, tin and iron
Iron, tin and calcium
- The recent atomic weight scale is based on
- Rust is
- Water has maximum density at
- Which of the following characters is not shown by hydrogen
- One fathom is equal to
- What is the unit for measuring the pitch or frequency of sound ?
- Which of the following parts of the sun is easily visible only during a total solar eclipse?
- The marine animal called dugong which is vulnerable to extinction is a/an
- The hardest substance available on earth is
- Permanent hardness of water can be removed by adding
- The most important ore of Aluminium is
- The formula of Plaster of Paris is
- Lightening cause rainfall because
- Quartz crystals normally used in quartz clocks etc. is chemically
- When a gas is turned into a liquid, the process is called
- Apparatus invented by Archimedes is :
- Old-written material, which cannot be read easily can be read by
- Glass is made from the mixture of
- The metal used in storage batteries
- According to Daltons atomic theory the smallest particle which can exist independently is
- Carbon tetrachloride fire extinguisher should not be used in closed room because it produces poisonous…
- The solar eclipse occurs when
- The intencity of Earthquakes is measured on
- In a certain electronic circuit the output is positive if input 1 is positive and input 2 is zero. If…
- Which of the following is the lightest metal ?
- Brass gets discoloured in air due to the presence of which gas in air
- In an atomic nucleus, neutrons and protons are held together by
- Which of the following elements is non-radioactive?
- The colour of Emerald is
- The fastest acting enzyme in the biological kingdom is