Olympiad Science - Some Natural Phenomena
Exam Duration: 45 Mins Total Questions : 30
What is the force present between two charged bodies called?
- (a)
Electrostatic force
- (b)
Electromagnetic force
- (c)
Gravitational force
- (d)
Frictional force
The force of attraction or repulsion between two charged bodies is called electrostatic force
What happens when two bodies are rubbed against each other?
- (a)
They acquire equal and similar charges
- (b)
They acquire equal and opposite charges.
- (c)
They acquire different charges but in different amounts depending upon their masses
- (d)
They do not acquire
During electrification by friction, one body loses electrons and gets positive charge and another gains these electrons and gets an equal amount of negative charge.
Suppose you are in a car and there is a thunderstorm. Which of the following is the best way to protect yourself from possible harm?
- (a)
Remaining in the car
- (b)
Getting out of the car and taking cover under the car
- (c)
Running to a nearby tree
- (d)
Getting out and standing under an electric pole
During thunderstorm and lightning, no open place is safe. If you are travelling by car,you are safe inside with the windows and doors of the vehicle closed. The rubber tyres of the cars are nonconductors, so you will be safer inside the car. All other options (tree, pole) have greater chances of electrocution. (A house or a building is a safe place too.)
What is the 5.1.unit of electric charge
- (a)
Coulomb
- (b)
Ampere
- (c)
Volt
- (d)
Watt
Electric charge is measured in 'coulomb'.
What happens when an ebonite rod rubbed with fur and a glass rod rubbed with silk are brought near each other?
- (a)
They attract each other
- (b)
They repel each other.
- (c)
Nothing happens to them.
- (d)
They acquire he
The charge on the ebonite rod rubbed with fur is negative (as it gains electrons). The charge on the glass rod rubbed with silk is positive (as it loses electrons). So, when these two rods are brought close to each other, they attract, since unlike charges attract each other.
What are lightning rods made up of?
- (a)
Copper
- (b)
Plastic
- (c)
Bakelite
- (d)
Sand paper
Lightning rods are made up of iron or copper (good conductor)
What is the purpose of an electroscope?
- (a)
To detect and test small electric charges
- (b)
To calculate the amount of electric charge flowing through the conductor
- (c)
To find out the presence of antimatter
- (d)
To test the presence of magnetic field
Electroscope isa device used for detecting and testing charges of small magnitude in a body. They are of two types - the pith ball electroscope and the gold leaf electroscope.
Why is a lightning conductor installed on a building?
- (a)
So that it collects the electric power present in the lightning
- (b)
So that it repels the lightning that falls on the building
- (c)
So that it forces the lightning to fall in an area where there are no buildings
- (d)
So that it conducts electric charge to the ground when lightning strikes the building
A lightning conductor is a metallic device installed on tall buildings to protect them from lightning striking the building during a thunderstorm. The charge from the lightning gets 'attracted' to the conductor. All the charge then flows through it to the ground instead of to the building.
What happens when a glass rod is rubbed with silk cloth?
- (a)
Electrons are added to it
- (b)
Electrons are removed from
- (c)
Protons are added to it.
- (d)
Protons are removed from it
When a glass rod is rubbed with silk cloth, it loses electrons and acquires positive charge
When you touch a charged body, the charge flows through you into the earth. What is this called?
- (a)
Induction
- (b)
Conduction
- (c)
Capacitance
- (d)
Earthing
The process of a charge being conducted from a charged body to the earth is called earthing. Earthing protects us from electrical shocks due to leakage of electrical current and from lightning during a thunderstorm and rain.
What is the nature of electrical charges generated by rubbing two objects?
- (a)
Static
- (b)
Mobile
- (c)
Positive
- (d)
Negative
The electrical charges generated by rubbing two objects are static and they do not move by themselves.
When we remove polyester or woollen clothes in dark, we can see a spark and hear a crackling sound. Which of the following is responsible for it?
- (a)
Static electricity
- (b)
Current electricity
- (c)
Positive charge
- (d)
Negative charge
The discharge of static electricity produces a spark.
Which of the following allows the transfer of electric charge from one charged object to another
- (a)
Vacuum
- (b)
Air
- (c)
Insulator
- (d)
Conductor
Electrical charge passes through a conductor
What is the lightning streaks that we see?
- (a)
UV rays from the sun
- (b)
Cosmic rays
- (c)
Accumulated electric charges
- (d)
IR rays from the sun
The accumulated negative and positive electric charges combine to produce streaks of bright light/ lightning
Which of the following is the safest way to protect yourself from lightning?
- (a)
Run into an open field
- (b)
Open an umbrella for cover
- (c)
Take shelter under a tree
- (d)
Squat low on the ground
Squatting low on the ground will make you the smallest target to be struck. In all other cases, you are exposed to the atmosphere
Which of the following countries in the world is most prone to earthquakes?
- (a)
India
- (b)
America
- (c)
China
- (d)
Japan
Japan is most prone to earthquakes. People of Japan construct their buildings in such a way that these can withstand major tremors
What are high speed winds accompanied with?
- (a)
Increased pressure
- (b)
reduced pressure
- (c)
Water vapour
- (d)
Static electricity
Moving air is called wind. It flows from areas of higher pressure to areas of lower pressure
By which of the following methods can a body be charged?
- (a)
Conduction
- (b)
Induction
- (c)
Friction
- (d)
All of the above
A body can be charged by conduction, induction and friction.
Which natural calamity cannot be predicted accurately in advance?
- (a)
Flood
- (b)
Cyclone
- (c)
Earthquake
- (d)
Famine
An earthquake is a sudden shaking or trembling of earth. It is so sudden that it cannot be predicted in advance.
On which of the following scales is the magnitude of an earthquake measured?
- (a)
Celsius
- (b)
Richter
- (c)
Fahrenheit
- (d)
Both (A) and (B
The power of an earthquake is expressed in terms of its magnitude on a scalebcalled Richter scale.
In which of the following states is an earthquake most likely to occur?
- (a)
Gujarat
- (b)
Chhatisgarh
- (c)
Chennai
- (d)
Kerala
In India, earthquakes most likely occur in Gujarat.
Which of the following is caused by electric spark?
- (a)
Thunder
- (b)
Lightning
- (c)
Storm
- (d)
Cyclone
The jumping of electrons between the two patches of clouds bearing different charges results in a big spark. The spark is seen as a flash of lightning.
According to the law of electrostatics
- (a)
a charged body attracts similar charged bodies but repels uncharged bodies.
- (b)
a charged body attracts bodies carrying similar charge and repels bodies possessing opposite charge.
- (c)
a charged body repels bodies possessing similar charge and attracts bodies with opposite charge
- (d)
a charged body attracts all types of charged bodies
Like charges repel and unlike charges attract each other
Which of the following is/are affected during lightning?
- (a)
T.V.
- (b)
Radio
- (c)
Telephone
- (d)
All of the above
Lightning affects radio and T.V.signalS resulting in the disturbance in the sound and picture clarity. It also affects the telephone wires and cause death of people when sparks of lightning fallon them.
How is lightning useful to us?
- (a)
It helps in nitrogen fixation and promotes plant gro
- (b)
Ozone is formed which prevents ultraviolet rays falling on the earth
- (c)
It helps in the evolution of a new species.
- (d)
All of the above
Statement (A), (B)and (C) list out the uses of lightning
What happens when water vapour changes to liquid in the form of rain drops?
- (a)
Heat is absorbed
- (b)
Heat is released.
- (c)
Heat is first absorbed and then released
- (d)
There is no release of heat
The energy contained in the gaseous form (vapour) is more than the energy contained in the liquid form (water). Therefore, when vapour changes to water it loses some heat.
Which of the following statements is NOT true?
- (a)
Lightning and sparks from woollen clothing are essentially the same phenomena.
- (b)
When you rub a plastic scale on dry hair, it acquires charge.
- (c)
A glass rod when rubbed with silk acquires negative charge
- (d)
Static charges are called so, because they do not move by themselves.
A glass rod when rubbed with silk acquires positive charge.
Earthquakes at two places M and N were measured as 2 and 4. How is the magnitude and their destructive energy at M and N related?
- (a)
Tremor at N is strong as that at place 'M'.
- (b)
Tremor at N is four times stronger than that at place 'M'.
- (c)
Tremor at N is 100 times stronger than that at place 'M'.
- (d)
Tremor at N is 1000 times stronger than that at place 'M'.
Richter scale is not a linear scale. It is a logarithmic scale. A difference in magnitude of'2' implies a multiplication factor of 100.
Where is the crust of the earth the thickest?
- (a)
At the continents
- (b)
At the ocean
- (c)
At the poles
- (d)
Near faults
The outer layer of the earth, on which we live is called the crust. The thickest part of the earth's crust is the continent.
Which of the following events can cause an earthquake?
(i) Movement of earth's plates
(ii) Volcanic eruption
(iii) Underground nuclear explosion
- (a)
Only (i) and (ii)
- (b)
Only (ii) and (iii)
- (c)
Only (i) and (iii)
- (d)
(i), (ii) and (iii)
An earthquake is usually caused by the movement of earth's plates. Apart from this, it is also caused by a meteor hitting the earth, volcanic eruption and underground nuclear explosion.