Q1) Biogas is produced from biomass by ________.
a) Destructive distillation
b) Anaerobic fermentation
c) Fractional distillation
d) Dry distillation
Solution
Biogas is produced from biomass by Anaerobic fermentation.
| Biogas | Produced from raw organic materials such as agricultural waste, manure, plant material, sewage and food waste. |
|
Destructive distillation |
It is the process of separation of solid components from a mixture by heating in the absence of air. Examples: coal tar, coke, oils and gases. |
|
Fractional distillation |
It is the process of separation used to separate liquid mixtures based on the difference in boiling points. Examples: kerosene oil and separation of natural gas. |
|
Dry distillation |
It is the process of heating of solid materials to produce gaseous products. Examples: wood, oil shale and coal. |
Q2) A lemon kept in water in a glass tumbler appears to be bigger than its actual size when viewed from the sides. What is the reason behind this phenomenon?
a) Diffraction of light
b) Internal reflection of light
c) Refraction of light
d) Reflection of light
Solution
Refraction of light
CONCEPT
- Refraction of Light: The bending of the ray of light passing from one medium to the other medium is called refraction.
- The refraction of light takes place on going from one medium to another because the speed of light is different in the two media.
- The greater the differencein the speeds of light in the two media, the greater will bethe amount of refraction.
- A medium in which the speed of light is more is known as optically rarer medium and a medium in which the speed of light is less is known as an optically denser medium.
EXPLANATION
- A lemon kept in water in a glass tumbler appears to be bigger than its actual size when viewed from the sides. This is because of the refraction of light. Therefore option 3rd is correct.
- Light is refracted as it passes from water into the air and as we know the refracted ray bends away from normal when it passes from denser to rarer medium.
- Water in a glass tumbler has a round outer surface that is convex and is a magnifying glass.
- As light is bent and being bent to the point that the object being observed appears to be larger than its normal size.
Q3) Prostate gland is present below ________.
a) The kidneys
b) the scrotum
c) The urinary bladder
d) The penis
Solution
The urinary bladder
- The prostate gland is present below the urinary bladder.
- The prostate gland in male helps to control urination from the bladder.
- The prostate is a gland connected to the testicles at one end and the penis on the other end.
- While ejaculation the prostate stores semen and makes fluid which liquefies it before it ejects out of the penis.
- DIAGRAM
Q4) Energy possessed by an object by its position or configuration is called ________.
a) Potential energy
b) Kinetic energy
c) Electrical energy
d) Nuclear energy
Solution
Potential energy
- The energy possessed by an object by its position or configuration is called Potential energy.
- Examples: climbing up on the chair and lifting heavy item to some height.
|
Types of Energy |
Description |
|
Kinetic energy |
It is energy due to the motion of an object. Examples: a car travelling down the road and an insect flying. |
|
Electrical energy |
It refers to energy that resulting from the flow of electric charge. Examples: transported materials and light bulb. |
|
Nuclear energy
|
It is an energy that is derived from the nucleus of an atom and which contains neutron and proton. Examples: the nuclear power plant and a nuclear bomb. |
Q5) Which component of the blood transports food, CO2 and nitrogenous waste?
a) WBCs
b) Blood platelets
c) Plasma
d) RBCs
Solution
Plasma
- Plasma: The liquid component of blood which performs the function of transportation of food, carbon dioxide, nitrogenous waste.
- It transfers dissolved substances such as nutrients and electrolytes etc. It also carries blood components throughout the body.
|
WBCs(White blood cell) |
It protects the body against infection and disease. |
|
Blood platelets
|
It helps to stop bleeding by clumping and clotting blood vessel injuries. |
|
RBCs(Red blood cells) |
It takes up oxygen from the lungs and circulates it around the body through the circulatory system. |
Q6) Which of the following causes damage to bridges, iron railings and all objects made of metals?
a) Corrosion
b) Rancidity
c) Acidity
d) Reduction
Solution
Corrosion
- Corrosion causes damage to bridges, iron railings and all objects made of metals.
- Corrosion is a process where metals are attacked by moisture, acids etc.
- Corrosion is the black coating that develops on articles made of silver or the green coating on copper articles.
|
Rancidity |
It is the spoilage-of food where it becomes unsafe for consumption. Rancidity changes the food colour, odour and flavour. It occurs mostly for oils. |
|
Acidity |
It is caused by excess production of acid by the gastric glands of the stomach. |
|
Reduction |
It refers to the addition of electrons, which leads to a reduction in oxidation number of the atom. |
Q7) The speed of sound in air at 0°C is________.
a) 330 ms
b) 330 ms-1
c) 331 ms
d) 331 ms-1
Solution
Corrosion
The speed of sound in air at 0°C is 331ms-1 or around 1200 km per hour.
Speed of sound (m/s) = 331 + 0.60 T(°C)
Hence, the speed of sound in air at 0°C is 331ms-1.
Q8) Which of the following is NOT a characteristic of dicotyledons plants?
a) These plants have 2 cotyledons
b) These plants have fibrous roots
c) These plants have reticulate venation
d) These plants have a tap root
Solution
These plants have fibrous roots
- Fibrous roots is not a characteristic of dicotyledons plants.
- Its roots develop from radicle and the seed has two cotyledons or embryonic leaves.
- Their leaves have reticulate venation and have a pentamerous and tetramerous flower.
- Examples: mustard, bitter gourd, watermelon, brinjal, apple, mango, tamarind etc.
Q9) A rocket is launched to travel vertically upward with a constant velocity of 20 m/s. After travelling for 35 seconds, the rocket develops a snag and its fuel supply is cut off. The rocket then travels like a free body. The height achieved by it is:
a) 700m
b) 800m
c) 680m
d) 720m
Solution
720m
Given:
A rocket is launched to travel vertically upward with a constant velocity of 20 m/s.
Concept used;
we know that S = ut
when it is moving at a constant velocity.
Calculation:
After 35 seconds the distance will be = S = 20 × 35
⇒ 700 m
Now from 700 m above the ground now it travels in a free fall.
The initial velocity = 20 m/s
Final velocity = 0
Acceleration due to gravity = -10
Now,
⇒ V2 = U2 + 2gs
⇒ 0 = 400 - 20S
⇒ 20s = 400
⇒ S = 400/20
⇒ S = 20 m
The height achieved = 700 + 20 = 720 m
∴ The required answer is 720 m.
Q10) What is the name the Russian chemist who stated that the properties of elements are a periodic function of their atomic masses?
a) Mendeleev
b) Zelinsky
c) Zaitsev
d) Markovnikov
Solution
Mendeleev
CONCEPT:
- Dmitri Mendeleev, the Russian chemist formulated a periodic law which states that the properties of elements are a periodic function of their atomic masses.
EXPLANATION
- Mendeleev was the most important contributor to the early development of the Periodic table.
- He categorised 63 elements on the basis of their physical and chemical properties in the increasing order of the atomic masses.
- Mendeleev’s periodic table was based on the mass number. This relation is known as "periodic law".
Additional Information
- Mendeleev's periodic table contains vertical columns called groups and horizontal rows called periods.
- He placed elements having similar properties in the same group. For example, Cobalt (atomic mass 58.9) was placed before nickel (atomic mass 58.7).
- He predicted the existence of certain elements that had not been discovered at that time and named them as Eka-Carbon, Eka-Aluminium, Eka-Silicon.
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