When one strikes a safety match, the first step is:
burning of sulphur
decomposition of potassium chlorate into potassium chloride and oxygen
conversion of a small amount of red phosphorus into white phosphorus
burning of glue and starch
C.
conversion of a small amount of red phosphorus into white phosphorus
A match is a small stick of wood or strip of cardboard with a solidified mixture of flammable chemicals deposited on one end. When you strike a match the red phosphorus is converted to white phosphorus for a fraction of a second, just enough to cause a spark of heat by reacting with oxygen in the surrounding air.
The LPG cooking gas contains propane and butane as the constituents. A sulphur containing compound is added to the LPG, because:
it lowers the cost of production
it enhances the efficiency of LPG
it facilitates easy detection of leakage of the gas
it assists in liquefying hydrocarbons
A plant having yellow leaves with dead spots has the deficiency of:
Potassium
Magnesium
Nitrate
Phosphate
Which one of the following statements is correct?
Covalent bonds are directional
Ionic bonds are directional
Both covalent and ionic bonds are directional
Both covalent and ionic bonds are non-directional
A horse and a donkey can breed to produce mule which is an infertile animal. The infertility is because horse and donkey belong to different:
class
order
species
genus
Along a streamline flow of fluid:
the velocity of all fluid particles at a given instant is constant
the speed of a fluid particle remains constant
the velocity of all fluid particles crossing a given position is constant
the velocity of a fluid particle remains constant
A particle is executing simple harmonic motion. Which one of the following statements about the acceleration of the oscillating particle is true?
It is always in the opposite direction to velocity
It is proportional to the frequency of oscillation
It is minimum when the speed is maximum
It decreases as the potential energy increases
Fluoride toothpaste is sometimes recommended because fluoride:
prevents plaque formation
hardens the enamel of the tooth
kills pathogenic bacteria
prevents tooth ache
How is the kinetic energy of a moving object affected if the net work done on it is positive?
Decreases
Increases
Remains constant
Becomes zero
