Science Quiz for NDA, CDS and CAPF Exam:18 August


Dear Aspirants, Science is an important subject in various exams like NDA, CDS, AFCAT, CAPF and other Police Exams. Here at Defence Adda we provide you with the quizzes based on the syllabus and pattern of these exams. The questions asked are of 10+2 level and preparing with a wide variety of questions will only help you ace in these exams. Here is a quiz based on the latest syllabus of these exams and covering various topics like Quantum Mechanics, Light, Thermodynamics, Magnetism etc to help you prepare with a wide variety of questions. 
Q1. Why does ice covered in sawdust not melt quickly?
(a) Sawdust does not allow the air to touch the ice
(b) The water is absorbed by sawdust
(c) Sawdust is a bad conductor of heat
(d) Sawdust is good conductor of heat

Q2. The washing machine works on the principle of ____________
(a) Dialysis
(b) Diffusion
(c) Reverse osmosis
(d) Centrifugation

Q3. An air bubble in water will act like a: 
(a) Convex mirror
(b) Convex lens
(c) Concave mirror
(d) Concave lens

Q4. The frequency of direct current is ____________
(a) Zero
(b) 50 HZ
(c) 60 HZ
(d) 100 HZ

Q5. If a body is moving on a circular path, what is its average velocity if it completes one cycle in one second?
(a) Average velocity depends upon time taken to complete one cycle
(b) One
(c) Average velocity is same as average speed
(d) Zero

Q6. Carnotite is an ore/mineral of _________. 
(a) Beryllium
(b) Chromium
(c) Uranium
(d) Copper

Q7. There is a protocol signed to reduce production of CFC, known as -
(a) CFC Protocol
(b) IR Protocol
(c) Montreal Protocol
(d) UV Protocol

Q8. Malachite is an ore/mineral of -
(a) Lead
(b) Manganese
(c) Mercury
(d) Copper

Q9. Which among the following will be a negative ion?
(a) If it has more electrons than protons
(b) If it has more electrons than neutrons
(c) If it has more protons than electrons
(d) If it has more protons than neutrons

Q10. Why metals conduct electricity?
(a) Because of low melting point
(b) Because of high tensile strength
(c) Because of free electrons
(d) Because of high atomic density

Solutions

S1. Ans.(c)
Sol. Saw dust is used to cover ice because it is poor conductor of heat. It did not let the ice melt quickly, as it does not transfer the heat of the surrounding to the ice.

S2. Ans.(d)
Sol. The washing machine works on the principle of Centrifugation.

S3. Ans.(d)
Sol. Air is optically rarer than water, the ray of light bends away from the normal at the point of incidence when moving from water to air while it bends towards the normal while moving from air to water. It is clearly visible that the air bubble acts as a DIVERGING LENS (concave lens) in water.

S4. Ans.(a)
Sol. DC implies no changes in value. Frequencies of signals are defined by how many changes per time, e.g. 60 cycles per second. In case of DC with there are 0 changes per second. Hence the frequency of DC is zero.

S5. Ans.(d)
Sol. When a body is moving in a circular path, its average velocity when it complete one cycle in one second is zero.

S6. Ans.(c)
Sol. Carnotite an important uranium ore.

S7. Ans.(c)
Sol.The Montreal Protocol is an international environmental agreement with universal ratification to protect the earth’s ozone layer by eliminating use of ozone depleting substances (ODS) like CFC, which would otherwise allow increased UV radiation to reach the earth.

S8. Ans.(d)
Sol. Malachite is an ore/mineral of copper.

S9. Ans.(a)
Sol. Negative ion which is created by an electron gain and it has more electrons than protons.

S10. Ans.(c)
Sol. Metals conduct electricity because of free electrons.


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