Physics Questions for NDA, CDS & CAPF: 15th August


Dear Aspirants, Physics 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. When light passes from one medium to another, this phenomenon of change in its direction is called _____.
(a) Refraction
(b) Diffraction
(c) Propagation
(d) No option is correct

Q2. Who invented world’s first true radar and demonstrated its use?
(a) Fred Morrison
(b) A. H. Taylor and Leo C. Young
(c) Van Tassel
(d) W. K.  Roentgen

Q3. When we see an object, the image formed on the retina is ________.
(a) Real and inverted
(b) Real and erect
(c) Virtual and erect
(d) Virtual and inverted

Q4. Kinetic energy depends on
(a) the velocity or speed of the moving body
(b) the mass of the moving body
(c) the pressure of the moving body
(d) both mass and velocity of the moving body

Q5. In which form is the supplied heat energy stored during change in temperature of substance?
(a) Heat energy
(b) Kinetic energy
(c) Potential energy
(d) Both kinetic and potential energy

Q6. A galvanometer can be converted into a voltmeter by connecting with it a -
(a) High resistance in parallel
(b) Low resistance in parallel
(c) High resistance in series
(d) Low resistance in series

Q7. Even after sunset, the air near the Earth’s surface continues to receive heat due to:
(a) Insolation
(b) Terrestrial Radiation
(c) Conduction
(d) Convection

Q8. Assertion (A) : kinematic viscosity of all liquids increases as temperature of liquids increases
Reason (R) : Rise of temperature increases kinetic energy of molecules. 
Code: 
(a) Both (A) and (R) are true, and (R) is the correct explanation of (A).  
(b) Both (A) and (R) are true, but (R) is not the correct explanation of (A). 
(c) (A) is true, but (R) is false. 
(d) (A) is false, but (R) is true. 

Q9. Food gets cooked faster in a pressure cooker because- 
(a) Water starts boiling at a lower temperature due to high pressure 
(b) Water starts boiling at a higher temperature due to high pressure 
(c) Water boils only at 100° C but the heat content is higher at high pressure 
(d) Convection currents are set inside the cooker 

Q10. When a piece of ice floating in a glass of water melts, the level of water will: 
(a) Fall 
(b) Rise 
(c) Remain same 
(d) Fall or rise depends on the temperature of water  

Q11. If a gas is compressed to half of its original volume at 27°C, to what temperature should it be heated to make it occupy is original, volume? 
(a) 327°C
(b) 600°C
(c) 54°C
(d) 300°C  

Q12. Which of the following material is used in the solar panel?  
(a) Silicon 
(b) Copper 
(c) Nichrome 
(d) Platinum 

Q13. Red is used an as emergency or danger signal because -
(a) it is a striking colour 
(b) its wavelength is the longest 
(c) its low wavelength
(d) it has very high energy

Q14. Which one of the following SI unit is not correctly matched?
(a) Work-Joule
(b) Force-Newton
(c) Mass-kg
(d) Pressure-Dyne

Q15. Identify the mineral not associated with radioactive elements- 
(a) Monazite 
(b) Thorium 
(c) Beryllium  
(d) Chromium   

SOLUTIONS

S1.Ans.(a)
Sol. Refraction is the bending of light as it passes from one medium to another. The bending is caused by the differences in density between the two substances.

S2.Ans.(b)
Sol. A H Taylor and Leo C Young are inventor of first true radar.

S3. Ans.(a)
Sol. When we see an object, the image formed on the retina is real and inverted.

S4. Ans.(d)
Sol. The amount of translational kinetic energy that an object has depends upon two variables: the mass (m) of the object and the speed (v) of the object.

S5. Ans.(d)
Sol. Kinetic Energy is form of energy which is the supplied heat energy stored during change in temperature of substance.

S6. Ans.(c)
Sol. In order to convert a Galvanometer into voltmeter, a very high resistance known as "series resistance" is connected in series with the galvanometer.

S7. Ans.(b)
Sol. Even after sunset, the air near the Earth’s surface continues to receive heat due to Terrestrial Radiation.

S8. Ans.(d)
Sol. It is observed that kinematic viscosity of all liquids decreases as temperature of liquids increases and vice versa. This is due to temperature rise of molecules of which causes decrease in cohesive forces of the molecules. The increase in temperature causes the kinetic or thermal energy to increase and the molecules become more movable. 

S9. Ans.(b)
Sol. Food can be cooked faster in a pressure cooker since the boiling point of water increases with pressure. As the water boils, the steam produced cannot evaporate so the pressure inside the cooker increases. At higher elevations, atmospheric pressure is lower and therefore water boils at lower temperature. 

S10. Ans.(c)
Sol. We know that the mass of liquid displaced by the floating ice equals to the mass of the object. That’s why the ice caps float on water. Similarly, when an ice cube melts in a glass of water, the water level does not change as the melted water will occupy exactly the same amount of space as the ice under the water level previously occupied. 

S11. Ans.(a)
Sol. 
 .

S12. Ans.(a)
Sol. Silicon is a semiconductor material. When it is doped with impurities like gallium and arsenic its ability to capture the sun's energy and convert it into electricity. Hence it is used in Solar cells.

S13. Ans.(b)
Sol. Red is used an as emergency or danger signal because it has longest wavelength. It scattered the least by air molecules. The effect of scattering is inversely related to the fourth power of the wavelength of a color. So red light is able to travel the longest distance.

S14. Ans. (d)
Sol. Pascal is the unit of pressure in the international system of units (SI). Dyne is unit of force in CGS system. Clearly, option (d) is not correctly paired.

S15. Ans.(d)
Sol. All options except chromium are being used as nuclear fuel of radioactive elements.

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