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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.
| 4901. |
Which of the following plant growth hormone increases the yield of sugar by increasing the length of stem in sugarcane?A. CytokininB. EthyleneC. Gibberellic acidD. Auxin |
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Answer» Correct Answer - C Gibberellic acid is also known as weak acidic plant growth regulator. It increases the yield of sugar by increasing the length of stem in sugarcane. It is the only plant growth hornone that elongates the internodes to increase the height of the plant by causing an increase in the length of axis. |
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| 4902. |
Heterocysts present in Nostoc are specialsed forA. fragmentationB. nitrogen-fixationC. symbiotic relationD. food storage |
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Answer» Correct Answer - B Cynobacteria like Nostoc can fix nitrogen through a specific structure called heterocysts. They fix atmospheric `N_(2)` using niterogenase enzyme which gets inactivated in presence of oxygen. Hence, the heterocysts creates a micro anaerobic environment in them to facilitate nitrogen-fixation. |
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| 4903. |
The output waveform of a 555 timer is a. sinusoidalb. triangular c. rectangular d. elliptical |
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Answer» (c) rectangular |
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| 4904. |
The displace ment of a body at any time t after starting is given by `s=10t-(1)/(2)(0.2)t^2`. The velocity of the body is zero after:A. 50 sB. 100 sC. 80 sD. 40 s |
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Answer» Correct Answer - A `v=(ds)/(dt)=10-0.2t` For `v=0` `t=(10)/(0.2)=50`sec |
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| 4905. |
if `y=x^2sinx+(3x)/(tanx)`, then `(dy)/(dx)` will beA. `2xsinx+x^2cosx+(3tanx-3xsec^2x)/(tan^2x)`B. `2xsinx+(3xsec^2x-3tanx)/(tan^2x)`C. `(x^2cosx+2xsinx-(3tanx-3xsec^2x))/(tan^2x)`D. `(x^2cosx-2xsinx-(3tanx-3xsec^2x))/(tan^2)` |
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Answer» Correct Answer - A `y=x^2sinx+(3x)/(tanx)` `(dy)/(dx)=x^2(d)/(dx)sinx+sinx(d)/(dx)(x^2)` `+((tan)(d)/(dx)(3x)-3x(d)/(dx)(tanx))/(tan^2x)` `(dy)/(dx)=x^2cosx+2xsinx+(3tanx-3xsec^2x)/(tan^2x)` |
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| 4906. |
An orbit electron in the ground state of hydrogen has an angular momentum `L_(1)`, and an orbital electron in the first orbit in the ground state of lithium (dounle ionised positively) has an angular momentum `L_(2)`. Then :A. `L_(1) = L_(2)`B. `L_(1) = 3 L_(2)`C. `L_(2) = 3L_(1)`D. `L_(2) = 9 L_(1)` |
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Answer» Correct Answer - A Doubly ionised positively lithium ion is a hydrogen like atom. hence : `L = m v r = (nh)/(2 pi)` for both which depends only on the value of n Also for both n = 1 Hence , `L_(1) = L_(2) = (h)/(2 pi)` , Hence (1). |
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| 4907. |
A particle is performing sinple harmonic motion of period 2 sec. if the greatest speed is `5(m)/(s)` the speed `((m)/(s))` of particle when it is `(3)/(pi)` m from equilibrium is: |
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Answer» Correct Answer - 4 Angular frequency `omega=(2pi)/(2)=pis^(-1)` `vmax=omegaA` `4=piA` `impliesA=(4)/(pi)m` `v=omegasqrt(A^(2)-x^(2))` `=pisqrt((25)/(pi^(2))-(9)/(pi^(2)))=4(m)/(s)`. |
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| 4908. |
Two blocks of masses 6 kg and 3 kg are attached to the two ends of a massless spring of spring constant `2 pi^(2) N//m`. If spring is compressed and released on a smooth horizontal surface then find the time period (in seconds) of each block.A. 1B. 2C. 3D. 4 |
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Answer» Correct Answer - B `T = 2 pi sqrt((mu)/(k)),mu=(6 xx3)/(6+3) =2kg` |
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| 4909. |
The graph in the figure shows how the displacement of a particle describing S.H.M. varies with time. Which one of the following statements is not true ? A. the force is zero at time `(3T)/(4)`B. the velocity is maximum at time `T//2`C. the acceleration is maximum at time TD. the P.E = total energy at time T/2 |
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Answer» Correct Answer - B The velocity is maximum at time `T//2` |
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| 4910. |
A block of mass `m_(1)=1kg` is attached to a spring of force constant `k=24N//cm` at one end and attached to a string tensioned by mass `m_(2)=5kg` . Dedcue the frequency of oscillaitons of the system. If `m_(2)` is initially supported in hand and then suddenly released, find `(a)` instantaneous tension just after `m_(2)` is released . ltbr. `(b)` the maximum displacement of `m_(1)`. `(c)` the maximum and minimum tensions in the string during oscillations. |
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Answer» Correct Answer - A::B::C `T=2pisqrt((m_(1)+m_(2))/(K))` `=2pi sqrt((6)/(2400))=(pi)/(10)` `rArr f=(10)/(pi)` Instantaneous tension just after `m_(2)` is released will be zero as the spring is unstressed. Amplitude of `m_(1)=m_(2)g//K=25//12 cm`, hence maximum displacement of `m_(1) ` will be `25//6 cm`. |
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| 4911. |
A particle initially at rest on a frictionless horizontal surface, is acted upon by a horizontal force which is constant is size and direction. A graph is plotted between the work done (W) on the particle, against the speed of the particle, (v). If there are no other horizontal forces acting on the particle the graph would look likeA. B. C. D. |
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Answer» Correct Answer - D Work done= change in kinetic energy `w=1/2 mV^(2)` `:. Prop V^(2)`` graph will be parabolic in nature |
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| 4912. |
A block of mass 20 kg is acted upon by a force `F=30N` at an angle `53^@` with horizontal in downward direction as shown. The coefficient of friction between the block and the forizontal surface is `0.2`. The friction force acting on the block by the ground is `(g=10(m)/(s^2)`)A. `40.0 N`B. `30.0 N`C. `18.0 N`D. `44.8 N` |
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Answer» Correct Answer - C (Easy) Max. frictional force `f_(max) = mu N` `= mu (mg + F sin 53^(@))` `= 0.2(20 xx 10 + 30 xx) = 44.8 N` As applied horizontal force is `F cos 53^(@)` `= 18 N lt f_(max)`, friction froce will also be 18 N. |
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| 4913. |
At `t = 0`, a force `F = at^(2)` is applied to s small body of mass m at an angle `alpha` resting on a smooth horizontal plane. A. Velocity of the body at the moment it breaks off the plane is `sqrt((mg^(3))/(9 a tan^(2) alpha sin alpha))`B. The distance travelled by the body before breaking off the plane is `(mg^(2))/(12a sin alpha tan alpha)`C. Its acceleration at the time of breaking off the plane is `g cot alpha`.D. Time at which it breaks off the plane is `sqrt((mg)/(a sin alpha))` |
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Answer» Correct Answer - A::B::C::D For breaking off the plane `F sin alpha = mg` `rArr a t_(0)^(2) sin alpha = mg " " rArr t_(0) = sqrt((mg)/(a sin alpha))` Speed at time of breaking off, `v = underset(0)overset(t_(0))int (at^(2) cos alpha)/(m) dt = (at_(0)^(2) cos alpha)/(3 m)` `= (a cos alpha)/(3m) . (mg)/(a sin alpha) sqrt((mg)/(a sin alpha))` `sqrt((mg^(3))/(9a tan^(2) alpha sin alpha))` `= (F cos alpha)/(m) = (at_(0)^(2) cos alpha)/(m) = (amg)/(a sin alpha) . (cos alpha)/(m) = g` `cot alpha` `s = int v dt = underset(0)overset(t_(0))int (at^(3))/(3m) cos alpha dt` `= (a)/(12m) t_(0)^(2) = (a)/(12m) (m^(2) g^(2) cos alpha)/(a^(2) sin^(2) alpha)` `= (mg^(2))/(12a tan alpha sin alpha)` |
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| 4914. |
the _______ of toothpaste are located in the health and beauty section of the supermarket. A) quarts B) tubes C) pints D) sticks |
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Answer» Correct option is B) tubes |
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| 4915. |
Why does a compass needle get deflected when brought near a bar magnet? |
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Answer» The compass needle is a small magnet. That’s why when a compass needle is brought near a bar magnet, its magnetic field lines interact with that of the bar magnet. Hence, a compass needle gets defected near a bar magnet. |
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| 4916. |
When liquid medicine of density `rho` is to put in the eye, it is done with the help of a dropper. As the bulp on the top of the dropper is pressed, a drop forms at the opening of the dropper. We wish to estimate the size of the drop. We first assume that the drop formed at the opening is spherical because that requires a minimum increase in its surface energy. To determine the size, we calculate the net vertical force due to the surface tension T when the radius of the drop is R. When this force becomes smaller than the weight of the drop, the drop gets detached from the dropper. If the radius of the opening of the dropper is r, the vertical force due to the surface tension on the drop of radius R (assuming r ltltR) isA. `2pirT`B. `2piRT`C. `(2pir^(2)T)/(R)`D. `(2piR^(2)T)/(r)` |
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Answer» Correct Answer - c |
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| 4917. |
They all criticized me, but it wasn't my fault. A) slammed B) shaded C) shot |
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Answer» Correct option is A) slammed |
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| 4918. |
He rushed out of the room, ____ the door as he went. A) slam B) slamming C) slams D) slammed |
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Answer» Correct option is B) slamming |
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| 4919. |
Tom plays tennis well, but he’s not very good ________ basketball. A) in B) at C) on D) for |
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Answer» Correct option is B) at |
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| 4920. |
She plays tennis ____ that everyone thinks she is a professional player. A) so good B) very well C) too well D) so well |
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Answer» Correct option is D) so well |
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| 4921. |
A ball is projected at some angle with ground such that it is at a particular height two times at `t = 4s` and `t = 6s`. Find the maximum height of the projecticle during the motion.A. `50 m`B. `80 m`C. `125 m`D. `180 m` |
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Answer» Correct Answer - C `T = t_(1) + t_(2) 4 + 6 = 10s` `10 = 2 (u sin theta)/(g) = rArr u sin theta = 50 m//s` `H_("max") = (u^(2) sin^(2) theta)/(g) = 125 m` |
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| 4922. |
She swims ____ than I do. A) good B) well C) better D) too good |
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Answer» Correct option is C) better |
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| 4923. |
A spring balance fastened to the roof of a lift accelerating upwards indicates `120 N` as the weight of a `80 N` body. The acceleration of the lift is `(g = 10 m//s^(2))`. A. `5 m//s^(2)` upwardsB. `(20)/(3) m//s^(2)` upwardsC. `(10)/(3) m//s^(2)` upwardsD. `5 m//s^(2)` downwards |
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Answer» Correct Answer - A `m (g + a) = 120 " " mg = 80` `mg + ma = 120 " " m = 8` `80 + ma = 120` `ma = 40` `a = (40)/(8) = 5 m//s^(2)` |
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| 4924. |
Analyse the table and fill it suitably.Electric current intensity is made three timesHeat produced becomes.....(1)....In a circuit, fuse wire is connected in......(2)....Electric current intensity is reduced to 1/4Heat produced becomes.....(3)..... |
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Answer» (1) 9 times, (2) Series, (3) 1/16 times
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| 4925. |
Analyse the table and find out the factor that influences heat the most. |
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Answer» Intensity of current |
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| 4926. |
Choose the facts related to LED lamps from the given list.a. Require only a small quantity of power.b. UV rays are produced due to electric discharge.c. Not harmful to environment since there is no mercury.d. Intense light is produced when high voltage is applied. |
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Answer» a. Require only a small quantity of power. c. Not harmful to environment since there is no mercury. |
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| 4927. |
Complete the table suitably.Gas-filled in the discharge lampColourHydrogen(a) ......(b) ........Orange-redNitrogen(c) ......(d) .......Green |
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Answer» a. Blue b. Neon c. Red d. Chlorine
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| 4928. |
Classify the following as those suitable for fluorescent lamps and for arc lamps.a. The main part is carbon rods.b. The heating coil is coated with thorium oxide.c. used in searchlights.d. more harmful for the environment.e. more intense light.f. ultraviolet rays are produced. |
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Answer» Arc lamps: a. The main part is carbon rods. c. used in searchlights. e. more intense light. Fluorescent lamps : b. The heating coil is coated with thorium oxide. d. more harmful for the environment. f. ultraviolet rays are produced. |
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| 4929. |
Using the relation from the first pair, complete the other.Filament: Tungsten Heating coil: |
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Answer» Filament: Tungsten Heating coil: Nichrome |
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| 4930. |
What are the advantages of using tungsten as a filament? |
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| 4931. |
Define the term LED. |
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| 4932. |
What are the advantages of fluorescent lamps over incandescent lamps. |
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Answer» 1. Saves electrical energy to a greater extent. 2. The inconvenience caused by shadow is minimized. 3. The life of fluorescent lamp is about 5 times that of incandescent lamps. |
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| 4933. |
What are the advantages of using discharge lamps instead of incandescent lamps? |
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Answer» Loss of electricity in the form of heat is less, more life span, no shadow formation, more light is obtained, less consumption of electricity. |
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| 4934. |
Which material is used as filament of bulb? |
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Answer» Tungsten is used as filament of bulb. |
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| 4935. |
Find out the odd one which is not suitable for the advantages of LED.a. It requires only a small quantity of power.b. It is not harmful to environment.c. Ultraviolet fays are formed due to discharge. |
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Answer» Correct answer is: c. Ultraviolet fays are formed due to discharge. |
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| 4936. |
Which of the given material has the highest resistivity?a. Nichromeb. Copperc. Aluminiumd. Silver |
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Answer» Correct answer is: a. Nichrome |
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| 4937. |
Using the relation from the first pair, complete the other.Fuse wire : low melting pointTungsten: ………… |
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Answer» Fuse wire : low melting point Tungsten: High melting point |
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| 4938. |
If we apply 230 V for a device having 230 V and 400 W, what will happen the power of the device ?(increases, decreases, doesn’t change) |
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Answer» Power of the device will be decreases. |
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| 4939. |
A 400 W electrical device is designed to work in 100 V. What will be its power if the device is working in 100 V? |
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Answer» Resistance of the appliance R = \(\left(\frac{ V^2 }{P}\right)\) = \(\cfrac{100 \times 100}{400}\) = 25 Ω Power when connected in 100 V P = \(\left(\frac{ V^2 }{R}\right)\) = \(\cfrac{100 \times 100}{25}\) = 400 Ω |
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| 4940. |
What is the color of the light emitted by discharge lamp filled withnitrogen when it works ? |
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Answer» The color of the light emitted by discharge lamp filled with nitrogen when it works - Red |
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| 4941. |
The filament of a filament lamp is broken. It is rejoined and is lit again.a. What happens to the intensity of light from it? Describe the reason behind.b. Incandescent lamps are filled with nitrogen at low pressure. What is the advantage of doing so?c. You are given two filament lamps of resistance 75012 and 100012. Of these, which has more power? |
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Answer» a. Increases. Because resistance decreases and current increases when length decreasing. b. Nitrogen doesn’t expand over less change in temperature. At normal temperature it behave as a inert gas. It is plenty in atmosphere. c. 750 Ω |
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| 4942. |
What are the equations for calculating Power? |
Answer»
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| 4943. |
Consider the fig A and fig B.1. In which circuit does the bulb glow with high intensity?2. Remove one bulb from each circuit. What do you observe? In fig A In fig B3. Why do the bulbs in Fig A glow with maximum brightness? |
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Answer» 1.Circuit A [figure A] 2. In fig A : bulb glows In fig .A : bulb does not glow 3. Low resistance |
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| 4944. |
A few heating appliances are shown in the Examine any one of them and answer the following questions. Record the answers in the science diary.1. Name the part in which electrical energy changes into heat energy.2. Which material is used to make this part?3. What are the peculiarities of such substances? |
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Answer» 1. Heatingcoil 2. Nichrome: Heating coils are made of nichrome. It is an alloy of nickel, chromium and iron. 3.
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| 4945. |
How does an arc lamp help in rescue operations? |
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Answer» The intense light of arc lamps are used in search lights and rescue operations during night time. It is used to rescue the victims of natural calamities, boat accidents. |
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| 4946. |
You saw the bird from your window. Was it perched on the tree?(a) True(b) False |
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Answer» Correct answer is (a) True |
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| 4947. |
Analyse and describe the working of a microwave oven. |
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Answer» Microwave oven is a device which is used for heating effect of electric current. It produces heat without a heating coil. Eddy current is used in the working of microwave oven. The heat is generated as a result of microwave radiations. The water molecules are stimulated using ‘magnet one’ and thus attains high temperature. Metal utensils are avoided and the substances without water content are not heated by this. |
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| 4948. |
10 resistors of 2 Ω each are connected in parallel. Calculate the effective resistance. |
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Answer» R = \(\cfrac{2Ω}{10}\) = 0.2 Ω |
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| 4949. |
How many resistors of 176 Ω should be connected in parallel to get 5A current from 220 V supply?a. 2b. 3c. 6d. 4 |
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Answer» Correct answer is: d. 4 |
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| 4950. |
A semicircle conducting ring of radius R is placed in the xy plane, as shown in Fig. A uniform magnetic field is set up along the x-axis. No emf, will be induced in the ring if A. it moves along the x-axisB. it moves along the y-axisC. it moves along the z-axisD. it remains stationary |
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Answer» Correct Answer - A::B::C::D Since line joining the ends of the ring is parallel to B, hence no emf will be induced in any case. |
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