 General Knowledge Quiz (Previous Years) for CDS & CAPF: 31st July

Dear Students, Defence Adda is providing you all with this quiz on General Knowledge questions for NDA & Other Defence Exams.

Q1. When ice melts, its
(a) Volume decreases
(b) Volume increases
(c) Volume and mass both decrease
(d) Volume decreases while mass increases

Q2. In step-down transformer, the AC output gives the
(a) Current more than the input current
(b) Current less than the input current
(c) Current equal to the input current
(d) Voltage more than the input voltage

Q3. A rectifier is an electronic device used to convert
(a) AC voltage into DC voltage
(b) DC voltage into AC voltage
(c) Sinusoidal pulse into square pulse
(d) None of the above

Q4. Statement I: Pulling a lawn roller is easier than pushing it.
Statement II: Pushing increases the apparent weight and hence the force of friction.
(a) Both the statements are true and statement II is the correct explanation of statement I
(b) Both the statements are true, but statement II is not the correct explanation of statement I
(c) Statement I is true, but statement II is false
(d) Statement I is false, but statement II is true

Q5. It is difficult to cut things with a blunt knife because
(a) The pressure exerted by knife for a given force increases with increase in bluntness
(b) A sharp edge decreases the pressure exerted by knife for a given force
(c) A blunt knife decreases the pressure for a given force
(d) A blunt knife decreases the area of intersection

Q6. When deep sea fishes are brought to the surface of the sea, their bodies burst. This is because the blood in their bodies flows at very
(a) High speed
(b) High pressure
(c) Low speed
(d) Low pressure

Q7. A bus travels at a speed of 50 km/h to go from its origin of its destination at a distance of 300 km and travels at a speed of 60 km/h to return to the origin. What is the average speed of the bus?
(a) 54. 55 km/h
(b) 55 km/h
(c) 55.55 km/h
(d) 54 km/h

Q8. A device, which is used in our TV set, computer, radio set for storing the electric charge, is
(a) resistor
(b) Inductor
(c) Capacitor
(d) Conductor

Q9. Which type/types of pen uses/use capillary action in addition to gravity for flow of ink?
(a) Fountain pen
(b) Ballpoint pen
(c) Gel pen
(d) Both ballpoint and gel pens

Q10. If two conducting spheres are separately charged and then brought in contact
(a) The total energy of the two spheres is conserved
(b) The total charge on the two spheres is conserved
(c) Both the total energy and the total charge are conserved
(d) The final potential is always the mean of the original potential of the two spheres

SOLUTION
S1. Ans.(a)
Sol. When ice melts its density increases i.e. its volume decreases. Mass is an invariant quantity.

S2. Ans.(a)
Sol. In step-down transformer Np>Ns,Ep>Es,Ip<Is
Here N, E and I used for no. of turns, emf and current respectively.

S3. Ans.(a)
Sol. A rectifier is used to convert AC voltage into DC voltage and inverts converts DC voltage into AC voltage.

S4. Ans.(a)
Sol. It is easier to move anybody by pulling it than by pushing it. A body starts to move when the applied force is more than the frictional force. This frictional force is proportional to the weight of the body under which it acts. When the lawn roller is pushed by the force (F), the vertical component of the pushing force now increases the weight (w = mg) of the roller which in turn results in increase of normal reaction and hence the friction is more.

S5. Ans.(c)
Sol. Pressure = force/area

S6. Ans.(b)
Sol. When deep sea fishes are brought to the surface of the sea, their bodies burst, this is because the blood in their bodies flows at very high pressure.

S7. Ans.(a)
Sol. Average speed = (total distance)/(total time)=(300+300)/(300/50+300/60)=54.55km/h
(∵Time=distance/speed)

S8. Ans.(c)
Sol. Capacitor is used to store energy in an electric field. Capacitance of a capacitor C, defined as the ratio of charge ± Q on each conductor to the voltage V between them.
C=Q/V

S9. Ans.(a)
Sol. Fountain pen uses capillary action in addition to gravity for flow of ink.

S10. Ans.(b)
Sol. If two conducting spheres are separately charged and brought in contact, then the total charge on the two spheres is conserved. This is the law of conservation of charge.