InterviewSolution
Saved Bookmarks
InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 1751. |
In a loud - speaker , sound is produced by a diaphragm on supplying electrical energy . Explain what type of motion the diaphragm exhibits while producing the sound ? How is sound produced in a loud speaker ? |
|
Answer» Solution :A diaphragm exhibits vibratory motion to produce sound . As the diaphragm MOVES forward , it compresses the air in front of it , HENCE , density of air increases at that place . This part of air causes NEXT layer of air to compress and the wave travels in the air with certain SPEED creating compressions . When a membrane moves BACKWARDS , it drags back the air layer near it decreasing the density of air in the adjacent layer. Thus , the wave advances in the air in the form of rarefaction . |
|
| 1752. |
A conductor AB is joined to a cell with its end A at a low potential and the end B at a high potential. (a} State the direction of flow of electrons in it. (b) What will be the direction of flow of conventional current in the conductor? |
|
Answer» SOLUTION :(a) The flow of electrons is from A to B (i.e., from a low potential to a HIGH potential). (b) The conventional current in conductor will flow from B to A (i.e., from a high potential to a low potential). |
|
| 1753. |
Thepitch of the screw in a screw jack shown in the figure is 5 cm and the diameter of thehead of its vertical shaft is 30 cm. If the length of the rod PQ fixed to the shaft is 55 cm, find the effort required to raise a load of 10.56 quintal using the jack. (Take 1 quintal = 100 kgwt) |
|
Answer» Solution :(i)Expression for M.A. of a screw jack (II) Find the effective length of the rod (lever) using the INFORMATION. (iii) Find the distance covered by theeffort for one complete rotation of the SHAFT. (iv) Find the mechanical advantage of the screw jack. (v) Relate M.A. with L and E. (VI) E = 120 kgf |
|
| 1754. |
Flash and thunder are produced simultaneously. But thunder is heard of few seconds after the flash is seen. Why? |
|
Answer» |
|
| 1756. |
What does the intensity of sound heard at a place depend on? |
|
Answer» Solution :The intensity of sound HEARD at a place depends on the FOLLOWING FACTORS, a. Amplitude of the source b. Distance of the observer C. Surface AREA of the source d. Density of the medium e. Frequency of the source. |
|
| 1758. |
A body moving with a constant acceleration travels the distances 3 m and 8 m respectively in 1 s and 2 s. Calculate : (i) the initial velocity, and (ii) the acceleration of body. |
| Answer» SOLUTION :(i) 2 m `s^(-1) ` (II) 2 m `s^(-2)` | |
| 1760. |
How can you experimentally prove that water is a bad conductor of heat? How is it possible to heat water easily while cooking. Experiment to prove that water is a bad conductor of heat: |
|
Answer» Solution :Take a glass tube and drop an ICE cube wrapped in wire gauge in it Now fill 3/4th of this tube with water and place it alwe the burner as shown in the FIGURE . You can OBSERVE that the water boils at the edge and the ice present in the bottom of the tube has not MELTED indicating that heat has not reached the bottom where the ice cube is present This proves that water is a bad conductor of heat. It is easy to heat water easily or quickly while cooking. This is because, while cooking thevessel or PAN is usually covered with a lid.  This leads to three things: (i) Radiation from the hot water in reflected back into the pan rather than being emitted (ii) Free convection is effectively eliminated, and (iii) Evaporative cooling is also eliminated. This in turn allows the water to be heated more easily . |
|
| 1761. |
An iron ball requires 5000 J heat energy to raise its temperature by 20^@C. Calculate the heat capacity of the iron ball. |
|
Answer» Solution :Given,Q=5000 J , `DeltaT=20^@C` or 20 K Heat Capacity , `C="Heat ENERGY required ,Q"/("Rise In temperature", DeltaT)=5000/20=250 JK^(-1)` |
|
| 1762. |
Find the distance travelled by a body in 5 minutes if it travels with a uniform speed of 20 m s^(-1) . |
|
Answer» SOLUTION :Given, u = 20 m `s^(-1)`, t = 5 min = `5 xx 60 s = 300` s Distance travelled S = `speed u xx `time t = 20 `m s^(-1) xx 300` S = 6000 m = 6 km. |
|
| 1763. |
Why do you fall fall in the forward direction when a moving bus brakes to a stop and fall backwards when it accelerates from rest. |
|
Answer» SOLUTION :In a moving bus, a passenger moves with the bus due to inertia of motion. As the DRIVER applies brakes, the bus comes to rest. But, the passenger tries, to maintain the inertia ofmotion. As a result a forward force is exerted on him. SIMILARLY, the passenger tends to fall BACKWARDS when the bus accelerates from rest because when the bus accelerates, the inertia of rest of the passenger tends to oppose the forward motion of the bus. HENCE the passenger tends to fall backwards when the bus accelerates forward. |
|
| 1764. |
An electric heater is rated 1500 W. How much energy does it use in 10 hour? |
|
Answer» ENERGY = power `XX` TIME `=1500Wxx10h` `=1.5kWxx10h=15kWh` |
|
| 1765. |
On what factors the pressure exerted by the liquid depends on? |
|
Answer» Solution :Pressure exerted by a liquid at a POINT is DETERMINED by, (i) DEPTH (h) (II) density of the liquid `(rho)` (III) acceleration due to gravity (g). |
|
| 1766. |
(a) Draw ray diagrams to show how the image is formed, using a concave mirror when the position of object is (i) at C (ii) between C and F (iii) between F and P of the mirror. (b) Mention the position and nature of image in each case. |
|
Answer» <P> SOLUTION :(a) (iii) Between the focus F and the pole P of the MIRROR  (B) 
|
|
| 1767. |
A car is moving with the initial velocity 15 m/s.Car stoped after 5s by application of breaks. Find the retardation (Decelaration). |
|
Answer» Solution :t = 5 s V =0 m/s u = 15 m/s u = 15 m/s a = ? Substituting the values in the FOLLOWING equation. v = u + at 0 = 15 + `(a xx 5)` a = `(-15)/(5)` a = - 3 `m//s^(2)` |
|
| 1768. |
The increase of carbon dioxide gas in atmosphere will cause |
|
Answer» DECREASE in temperature |
|
| 1769. |
Through which medium sound travels faster, iron or water? Give reason. |
| Answer» Solution :SOUND travels faster through iron as solids are PACKED TOGETHER TIGHTER than liquids and gases. | |
| 1770. |
Power of a water-pump is 2kW ………….. Litre of water can be lifted to a height of 10m in 1 minute. (600,1200,2000) |
|
Answer» |
|
| 1771. |
State whether the following quantity is a scalar or vector ? (a) pressure "" (b) force (c) momentum "" (d) energy (e) weight "" (f) speed. |
| Answer» Solution :(a) scalar (B) vector (c) vector (d) scalar (E) vector (f) scalar. | |
| 1772. |
Take a convex mirror. Hold it in one hand. Hold a pencil close to the mirror in the upright position in the other hand. Observe the image of the pencil in the mirror. Is the image erect or inverted? Is it diminished or enlarged ? Move the pencil slowly away from the mirror. Does the image become smaller or larger? What do you observe? |
| Answer» Solution :When we HOLD a PENCIL in the upright POSITION in front of a convex mirror we observe the image of the pencil at the back to the mirror. The image is erect, virtual and smaller in size than the object. As the pencil is moved away from the mirror, the image BECOMES smaller. When the object is moved away from the mirror, the image would move closer to the focus of the mirror. | |
| 1773. |
A boy purchases 2 litre of milk from a shop. To find out the extent of adulteration he constructed a device by using a capillary tube (T) and a cylindrical container (C ) as shown in the figure. In order to make the device float upto a mark (M), in pure milk, he adds 10 lead shots each of mass 5 g into it. To make the device float to the same mark in a sample of milk purchased, he removes one lead shot from it. The total weight of the device is 200 gwt. Determine the density of a dultered milk that the shopkeeper adds to the milk. Density of pure milk is 1.045" g cm"^(-3) and density of water is "1 g cm"^(-3). |
|
Answer» Solution :WEIGHT of the device + Weight of the LEAD shots = Volume of milk DISPLACED `xx` Density of milk `W+wxx=vxxd_(m)` (1) `W+wxxy=vxxd_("impure milk")` Compare (1) and (2) and DETERMINE `d_("impure milk")` |
|
| 1774. |
How do the following factors affect, if at all, the speed of sound in air : pressure of air |
| Answer» SOLUTION :No EFFECT | |
| 1775. |
The negative acceleration is also called as _________ . |
| Answer» SOLUTION :RETARDATION (or) DECELERATION | |
| 1776. |
A light ray is incident on air-liquid interface at 45^@ and is refracted at 30^@. What is the refractive index of the liquud? For what angle of incidence will the angle between reflected ray and refracted ray be 90^@? (AS_(7)) |
|
Answer» |
|
| 1778. |
What is meant by negative acceleration? |
| Answer» Solution :If v < U, i.e. if final VELOCITY is LESS than initial velocity, the velocity DECREASES with time and the value of acceleration is negative. It is called negative acceleration. It is also called as retardation (or) deceleration | |
| 1779. |
The frequency of a source of sound is 600 Hz. How many times does it vibrate in a minute? |
|
Answer» Solution :The number of vibrations (COMPLETE WAVES or cycles) produced in ONE second is called FREQUENCY of the wave. HENCE, in one minute `600xx60` vibrations are produced = 36000 (Need clarification) |
|
| 1780. |
Name any two appliances which work under the principle of heating effect of current. |
| Answer» Solution :The principle of all electric HEATING APPLIANCES like iron box, water heater, TOASTER etc. work under the principle of heating EFFECT of current. | |
| 1781. |
A person completes 5 rounds (revolutions) on a circular path of radius 50 m. Find out the distance travelled by that person and magnitude (value) of displacement. |
| Answer» SOLUTION :DISTANCE `= 1570 m,` the MAGNITUDE of DISPLACEMENT = 0 | |
| 1782. |
Light enters from air into a glass plate having refractive index 1.5. What is the speed of light in glass ? (c = 3 xx 10^(8) ms^(-1) ) |
|
Answer» SOLUTION :Given : Refractive index `(mu) = 1.5` Speed of LIGHT in vacuum (c ) `= 2 XX 10^(8) ms^(-1)` Speed of light in glass `(upsilon) = ?` Solution : `mu= ( "Speed of light in vacuum(c )")/("Speed of light in glass" (upsilon) )` `1.5 = (2 xx 10^(8) ms^(-1) )/(upsilon) rArr upsilon = (2 xx 10^(8) ms^(-1) ) /(1.5 ) = 1.3 xx 10^(8) ms^(-1)` `therefore` Speed of light in glass `= 1.3 xx 10^(8) ms^(-1)` |
|
| 1783. |
Does a solar cell always maintain the potential across its terminals constant? Discuss. |
| Answer» Solution :The electro-chemical PROCESS inside a BATTERY provides ELECTRONS at the negative terminal and draws electrons from the positive terminal to maintain the current being drawn. By providing energy to the electrons, the cell is capable of maintaining an electric potential difference across the two ends of the external CIRCUIT. | |
| 1784. |
In an arrangement of two wheel and axle systems, the radii of wheels are 20 cm and 15 cm and the radii of axle are 4 cm and 3 cm. Calculate E if L = 540 kg. |
|
Answer» Solution :Let `MA_(1)` and `MA_(2)` be the mechanical advantages of the UPPER and LOWERS wheel and axles, respectively `MA_(1)=(L_(1))/(E_(1))=(R_(1))/(r_(1) )"" (1)` Where ` L_(1)=540 KG wt`, `R_(1)=20 cm , r_(1)=4 cm` `MA_(2)=(C_(2))/(E_(2))=(R_(2))/(r_(2))` ` = (E_(1))/(E_(2))=(R_(2))/(r_(2)) "" (2)` From (1) `(540)/(E_(1))=(20)/(4)` `E_(1)=(540)/(5)=108 kg wt` `:.` From (2) `(108)/(E_(2))=(15)/(3) RARR (108)/(E_(2))=5` `E_(2)=(108)/(5)=21.6 kg` ` wt = 21.6 xx 9.8 = 211.68 N` |
|
| 1785. |
A concave mirror is placed on a table with its pole touching thetable . The mirror is rotated about its principal axis in clockwise direction. Theimage of a person lookingstraigth into it |
|
Answer» ROTATES in CLOCKWISE DIRECTION |
|
| 1786. |
A piece of stone of mass 113 g sinks to the bottom in water contained in a measuring cylinder and water level in cylinder rises from 30 ml to 40 ml.Calculate R.D. of stone. |
|
Answer» |
|
| 1787. |
Does a ship that enters a fresh water lake from the ocean sink more or rise move? Justify your answer. |
|
Answer» |
|
| 1788. |
Soni says that the acceleration in an object could be zero even when several forces are acting on it. Do you agree with her? Why. |
| Answer» SOLUTION :Acceleration in an object COULD be ZERO even when several forces are acting on it. This happens when all the forces CANCEL out each other i.e, the net force acting on the object is zero. Hence, the acceleration of the object is zero. Hence, Soni is right. | |
| 1789. |
A student sets up a slinky PQ on a smooth table top in the manner How can he produce transverse waves in the slinky by moving its free end Q ? . |
|
Answer» at an angle of `45^(@)` with the table top |
|
| 1790. |
Lifting a small stone to a certain height and then dropping it downwards. Did you apply any force on the stone to bring it down? |
|
Answer» |
|
| 1791. |
Name two factors which determine the momentum of a body. |
| Answer» SOLUTION :Two factors on which MOMENTUM of a BODY depend is mass and velocity . Momentum is DIRECTLY proportional to the mass and velocity of THEBODY. | |
| 1792. |
Distinguish Between Energy and Power |
| Answer» Solution :`{:(,"Energy",,"Power"),(1.,"Ability of an object to do WORK is called energy",1.,"Time rate of doing work is called power."),(,"of that object.",,),(2.,"The SI unit of energy is JOULE (J).",2.,"The SI unit of joule second"^(-1)(Js^(-1))" or watt (W)."):}` | |
| 1793. |
Name the type of energy passed by a raised hammer? |
|
Answer» |
|
| 1795. |
Does the law of consrevation of energy hold good in the production of X-rays ? Is the kinetic energy conserved? Discuss. |
|
Answer» Solution :Recall the nature of X-rays. All electromagnetic RADIATIONS consist of ENERGY. What are the other forms of energy PRODUCED along with X-rays in a discharge tube ? |
|
| 1796. |
We are familiar with Newton's laws of motion. State Newton's second law of motion. |
|
Answer» |
|
| 1797. |
If for a moving object, the distance-time graph is (half) parabola, then the object would be performing ......... motion. (uniform, with constant acceleration, non-uniform) |
| Answer» SOLUTION :non-uniform | |
| 1798. |
1 J equals to |
|
Answer» 0.24cal |
|
| 1799. |
Analyse the graphs given below. Which graph indicates uniform velocity? |
|
Answer» |
|
| 1800. |
A coin and a piece of paper are dropped simultaneously from the same height .Which of the two will touch the ground first ? What will happen if the coin and the piece of paper are dropped in vacuum ? Gives reasons for your answer . |
| Answer» | |