Olympiad Class 7 Science Mock Test Set 03

Question. An object is placed at 15 cm in front of a plane mirror. If the object is moved towards the plane mirror, which of the following changes will take place?
(A) The size of the image will become less than the size of the object.
(B) The distance between the image and the plane mirror decreases.
(C) The focal length of plane mirror decreases. 
(D) The image distance remains same.
Answer : B

Question. What kind of silk is rayon?
(A) Pure silk
(B) Impure silk
(C) Mulberry silk
(D) Synthetic silk
Answer : D

Question. An electrolyte is a
(A) solid that conducts electricity.
(B) liquid that conducts electricity and breaks up chemically in the process.
(C) liquid that does not conduct electricity.
(D) solid that does not conduct electricity.
Answer : B

Question. Which of the following fungi exhibit the characteristics given below?
X – Umbrella shaped fruiting body
Y – Mycelium lies beneath the surface of the soil
Z – Gills are the spore bearing organs
(A) Rhizopus
(B) Mould
(C) Yeast
(D) Mushroom
Answer : D

Question. Frictional force is independent of area of contact but still brakes of very small contact are not preferred. Why ?
(A) Friction depends on the nature of the material.
(B) Friction causes wear and tear.
(C) Friction resists motion.
(D) Friction caused is due to sliding friction.
Answer : B

Question. Which of the following is a good conductor of electricity?
(A) Tap water
(B) Distilled water
(C) Sea water
(D) Rain water
Answer : C

Question. Electric charge can flow through
(A) insulators.
(B) conductors.
(C) both insulators and conductors.
(D) neither insulators nor conductors.
Answer : B

Question. The sex of a child is determined by
(A) X chromosomes of mother
(B) Y Chromosomes of father
(C) Number of days between ovulation and fertilisation
(D) Number of days between fertilisation and implantation
Answer : B

Question. Which pair of instruments have both the higher amplitude and higher frequency of sound?
(A) Violin, Guitar
(B) Violin, Violin
(C) Guitar, Violin
(D) Guitar, Guitar
Answer : B

10 In which case is friction a disadvantage?
(A) running a machine
(B) walking
(C) applying brakes
(D) writing
Answer : A

Question. X is a black, thick liquid with unpleasant smell.
It is obtained during the processing of coal. It is used for preparing napthalene balls.
Identify X.
(A) Coke
(B) Coal gas
(C) Natural gas
(D) Coal tar
Answer : D

Question. Air pressure is also known as atmoshperic pressure. How is it caused?
(A) By the heat energy in the air
(B) By the wind that blows in the air
(C) By water vapour in the air
(D) By the air around us that presses on the surfaces of objects
Answer : D

Question. Identify the use of a seed drill.
(A) It is used to put manure or fertiliser near the roots of trees
(B) It is used to sow the seeds at equal distances
(C) It is useful to remove weeds in a field
(D) Both (A) and (B)
Answer : B

Question. How many dots does the Braille system use?
(A) 5
(B) 6
(C) 10
(C) 11
Answer : B

Question. Which of these can you use as a substitute for glass in windows?
(A) Polythene
(B) PVC
(C) Perspex
(D) Teflon
Answer : C

Question. On adding sulphur dioxide to water you get
(A) sulphur
(B) sulphur trioxide
(C) sulphurous acid
(D) sulphuric acid
Answer : C

Question. Observe the figure given below.

Identify the electrolyte Z.
(A) Silver nitrate
(B) Zinc sulphate
(C) Copper sulphate
(D) Potassium sulphate
Answer : C

Question. Which of the following will occur if the fallopian tube is ligated?
(A) Ovum will not be produced
(B) No fertilisation will occur
(C) Implantation of the zygote cannot occur
(D) No sex hormones will be produced
Answer : B

Question. The energy of vibrations measured on the Richter scale increases by steps of about
(A) 10
(B) 20
(C) 30
(D) 40
Answer : C

Question. Which of these activities help to maintain biodiversity?
I - Protect endangered species
II - Set up forest reserves
III - Clear land for agriculture
(A) I and II only
(B) I and III only
(C) II and III only
(D) I, II and III
Answer : A