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2801.

chargeExample 1.2 If 10 electrons move out of aevery second, how much time is required toget a totaalL 10 electrons move out of the ton the other body?

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2802.

If 10^9 electrons move out of a body to another bodyevery second, how much time is required to get a total chargeof 1C on the other body?tal charge of 1 c

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tq

not a satisfactory ans

2803.

The equation of a simple harmonic motion is given by x = 6 sin 10 t+ 8 cos10 t, where x is incm, and t is in seconds. Find the resultant amplitude.

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y = 6 sin10 t + 8 cos10 t

Let 6 = R sin theta8 = R cos theta

y = R sin theta.sin 10 t + R cos theta. cos10 t

y = R sin(10 t + theta)

Where R is the amplitude of wave and theta is initial phase.

R^2 = (6)^2 + (8)^2 R^2 = 36 + 64R = sqrt(100)R = 10

2804.

Determine the buoyant force acting on a solid of volume 1.6m3, immersed in seawater of density1030 kg m-3 (Take g=10 m/s2)1) 16480N 2) 164 N3) 1648 N4) 61840 N

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Buoyant force = volume × density × g

= 1.6× 1030× 10= 17992.8=16480 N

2805.

21. Two blocks of masses 2 kg and 4 kg are hanging with the help of massless string passing over an ideal pulleyinside an elevator. The elevator is moving upward with an acceleration The tension in the string connectedbetween the blocks will be (Take g = 10 m/s)(1) 40 N(2) 60 N(3) 80 N(4) 20 N

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Inside the lift the frame of reference (attached to the floor or celing)is moving up with an acceleration of g/2 upwards. So for applying Newton's laws, we need to add a pseudo force of mass*g/2 in the downward direction for each mass. In otherwords, we can say the effective g' = g + g/2 = 3g/2 downwards.

Since M1, the4 kilo mass is heavier, it will accelerate downwards with in the lift. M2, the 2kg mass will move upwards with the same acceleration as that of M1. We assume that the string is tight and so it has the same tension Tthrough the string. equations of motions for M1 and M2 are : M1 g' - T = M1 a => a = ( g'- T/M1) M2 a = T - M2 g' => T = M2 (a+g') = M2 (2g' - T/M1) T = 2 M2 g' - TM2 / M1 => T= 2 M1 M2 g'/ (M1+M2) T = 3 M1 M2 g / (M1+M2) = 3 *2 * 4 * 10 / (2+4) = 40 Newtons

option 1 is the answer

2806.

Example 89. A antri Ines,咿al kmgth 20 cm, t, placed co rially with a convex mirror e raliuso carature 20cm Thetuo are krpt 15 qrt frm nach other A pint objnct is placod 60 cm in front of the convex lens. Drate a ray diagram to shotethe formation of the image by the aahination. Deteremine the nature and psition of the image formed ICASE OD 14

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thanks

2807.

The force FE 3 & 4, acting on a bodyand due to this body displacedfindtheworld done.

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if you find my answer to be your benefit I will try to solve more questions of you

so tell me if you like my solutions

2808.

4. When 1 N force acts on 1 kg body that is able to movefreely, the body receives

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According to second law of motion

F=ma mass =1kg force =1Nif one Newton of force applied on the body of mass 1kg and it moves with an acceleration of 1 m/s^2.

The body receives 1 m/s^2.

2809.

C. SHORT-ANSWER QUESTIONS: Answer in a sentence or two.1. Why are standard units used in measurements?

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Standard unit of measurements provide a general reference point,

2810.

28. The acceleration-time graph for a particle movingY along x-axis is shown in figure. If the initial velocityof particle is -5 m/s, the velocity at t = 8 s isa (m/s)10/2461-10(1 F15 m/s(3) -15 m/s(2) +20 m/s(4) -20 m/sof 10 m pierce

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The concept here is that Area under acceleration time graph gives you the change in velocity.

From, 0 to 6s, Acceleration is positive. So, change in velocity = Area of upper triangle = 1/2 X Base X height= 1/2 X 6 X 10 = + 30 m/s

+ sign indicates that velocity is increasing.

From 6 to 8s, acceleration is negative. So, change in velocity= Area of lower triangle= 1/2 X Base X height= 1/2 X 2 X -10 = -10 m/s

- sign indicates that velocity is decreasing.

Total Area under Graph= Upper Triangle Area + Lower Triangle Area.= 30 - 10= 20 m/s

So, final velocity= Initial velocity + Total Area under Graph= -5 + 20= 15 m/s (Ans)

2811.

The uniform motion in the following acceleration-timegraph is-39.15a(m/s)102 4 6 8 10-5(A) AB(C) CD(B) BC(D) DE

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uniform motion is the motion in which speed is constant..

so, for speed to be constant.. the acceleration should be zero..

and the path is from A to B ..

so, option A.

2812.

gid Body Dyhamies4, Let l1 and l2 be moments of inertia of a body about two axes 1 and 2 respectively. The axis 1 passesthrough the centre of mass of the body but axis 2 does not(A) l1 12(C) If the axes are parallel, l1 s 12(B) If 11 < 12, the axes are parallel.(D) If the axes are not parallel, 11 2 12'm' remi maior axis 'r'

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2813.

eationsofSemiconL1me the logic gate which performs (a) multiplication and (b) inversion operation2. Draw a circuit diagram to shour the

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1. AND logic gate performs multiplication. NOT logic gate performs inversion operation.

2814.

Section (A): of centre of massA-1. Three particles of mass 1 kg, 2 kg and 3 kg are placed at the comers A, B and C respectively of anCalculationequilateral triangle ABC of edge 1 m. Find the distance of their centre of mass from A.

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tuje dikta nhi hai Kya jab bol diya wrong answer

2815.

A-1. Three partides of mass 1 kg, 2 kg and 3 kg are placed at the comers A, B and C respectively of anequilateral triangle ABC of edge 1 m. Find the distance of their centre of mass from A

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2816.

Three partides of mass 1 kg, 2 kg and 3 kg are placed at the corners A, B and C respectively of anequilateral triangle ABC of edge 1 m. Find the distance of their centre of mass from AA-1.

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2817.

s of mass 1 kg, 2 kg and 3 kg are placed at the corners A, B and C respectively of anequilateral triangle ABC of edge 1 m. Find the distance of their centre of mass from A

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wrong answer

2818.

tion (A): Calculation of centre of massThree partides of mass 1 kg, 2 kg and 3 kg are placed at the corners A, B and C respectively of anequilateral triangle ABC of edge 1 m. Find the distance of their centre of mass from A

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wrong answer Pehle bhi bola tha na

2819.

16. If A, B, C are mutually perpendicular, show that× (A ×B )=0. Is the converse true?

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2820.

12.A 120 g mass has a velocity V (2i+5j) m/ sat a certain instant. Its kinetic energy is:(a) 1.7 J(b) 4.0J (c) 5.0J (d) 6.0 J

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modules of velocity = √4+25= √29now kinetic energy = 1/2mv*v1/2*120*2917401.7Kgm^2/s^2

2821.

If velocity of a projectile is givenv 2i + 3j ms', then the range is:1) 1.2 m3) 0.6 m2) 2.4 m4) 3.6 m

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2822.

प्रश्न 12. एक T बीम (Beam) के फ्लैंज की चौ100 mm तथा पेटा की गहराई 150 mm है। फ्लैंजपेटा की मोटाई 10 mm है, यदि धरन की 4m कीसम्पूर्ण लम्बाई पर 2.5 kN/m का एक समान बंदितभार लगाया गया हो तो उसमें उत्पन्न अधिकतम तननप्रतिबल का मान ज्ञात कीजिये। धरन सिरों पर सरलआधारित है।(2008)

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260 hai please like kaar

2823.

12. Figure shows four paths for a kicked football. Ignoring theeffects of air on the flight, rank the paths according to initialhorizontal velocity component, highest first(a) 1, 2, 3, 4(c) 3, 4, 1, 2(b) 2, 3, 4, 1(d) 4, 3, 2, 1

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considering the motion to be projectile

maximum height is u²sin²∅/2g

so, if maximum height is same for all , and if ∅ is increased , the velocity should be reduced , to maintain the same height

so, 4 has less angle.. and 1 has maximum angle

=> velocity order is 4>3>2>1

option d

2824.

(A49 m(B9.6 m12. A particle of mass 0.01 kg is projected with velocity v 2i m/s from point (x 0,y 20). After 2 second,its position coordinates are-(B) 20,4(C) 0,4(D) 4, 20

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2825.

Newton's Laws of Motion and FrictionA bar of mass m, is placed on a plank of mass m, which rests on a smooth horizontal plane. The coefficient of frictionbetween the surfaces of bar and plank is k. The plank is subjected to a horizontal force F depending on time t as F - at,where a is a constant. The moment of time t, at which the plank starts sliding is :58.akgm +m2(m1 + m2)kg2)mim2ka(4) (m, + m2)3ka

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i think 2nd option is correct

plz inform me whether i am right or not

yes u r right

minimum force needed to overcome friction = k(m1+m2)g

now that force = F = at

=> at = k(m1+m2)g=> t = k(m1+m2)g/a

2826.

. A ring has a total mass M but non-uniformlydistributed over its circumference. The radiusof the ring is R. A point mass m is placed at thecentre of the ring. Workdone in taking awaythis point mass from centre to infinity is

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2827.

243A light inextensible string that goes over a smooth fixed pulley as shown inconnects two blocks of masses 0.36 kg and 0.72 kg. Taking g 10 m/s, find thedone (in joules)the system is released from rest.workby the string on the block of mass 0.36 kg during the first second after[JEE 2009, 4/160, -1]

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2828.

2.23 The voltage gain A of the circuit shown below13.7 Volts312k100 k22HW10k 2B = 100

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2829.

2.23 The voltage gain A of the circuit shown belowis13.7 Volts{12 kn100 k123How10kB = 100

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2830.

2.23 The voltage gain A of the circuit shown below13.7 Volts{12k0100 k.223B = 10010k22

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2831.

40.The value of effective resistance between A and Bis ? (R = 2 k22)A26REWWWBO

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2+2+2 {series R} =66 ll 26*2/6+2=1.52+1.5+2=5.55.5*2/5.5+2=1.4662+1.466+2=5.466

2832.

2.23 The voltage gain A of the circuit shown below13.7 Volts{12 kg100 KOSVWIRB = 100to10 k

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2833.

The half-life of a radioactive element is 5 days In how many days will the 16 g of theelement will toduce to 2 g ?

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Decreasing from 16 g to 2g is a decrease by a factor of 8 = 2^3 This requires three half-lives.

2834.

Calculate the amount of work done in moving a body up a rough inclined p

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1

2835.

5. Nucleolus is present in(1) Cytoplasm of prokaryotic cells(2) Nucleoid of prokaryotic cells(3) Cytoplasm of eukaryotic cells(4) Nucleus of eukaryotic cells

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the correct answer is option (d) because nucleolus is present in nucleus which is only present in eukaryotes

thank you

2836.

t bojeerh รถrder to bringtne object to rest?Calculate the work required to be done to stop a car of 1500 kgmoving at a velocity of 60 km/h?17.

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2837.

A spring of spring constant 8Ncm-l has an extension 5cm. The minimum work done in joules inincreasing the extension from 5 cm to 15cm is1) 43) 84) 10

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2838.

A battery of 20 cells (each having e.m.f 1.8Vand internal resistance 0.1ohm) is chargedby 220 volts and the charging current is 15A.The resistance to be put in the circuit isQ.29) 10.27 ohnm(C) 8.62 ohms(B) 12.27 ohm(D) 16.24 ohms

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Using Kirchoff'sVoltage Law the following eqn results220 = 20x1.8 + 15x20x0.1 + 15xR (where R is the external resistance required)or 15R = 220 - 36 -30.or 15R = 154or R = 10.3 ohms.

2839.

0.3. How much work is done in moving a charge of Scoulomb from a point at the voits 115 to a pointat 125 volts?

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Work done = Q(potential difference between the two points).W = 3(125-115)W = 30 J

2840.

35, A projectile is thrown with velocity v at an angle θwith horizontal. When the projectile is at a heightequal to half of the maximum height, the verticalcomponent of the velocity of projectile is(1) v sin e x 3(2) Ysine3v sin θa)V2V3

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2841.

0.18 Evaluate\int\left(\frac{t \sqrt{t}+\sqrt{t}}{t^{2}}\right) d tt2 t^{\frac{1}{2}}+\frac{2}{\sqrt{t}}+c2 t^{\frac{1}{7}}-\frac{2}{\sqrt{t}}+c(\mathrm{C})^{\frac{1}{3}}+\frac{3}{\sqrt{t}}-c

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2842.

30. A brick has 3 sides a, b.c fa> b> c). The brick can be kept on ground on any face. The work required ndone to move from minimum potential energy to maxir m potential energy is:(A) mg(a/2-b/2)(3 ) (B) mg(a/2-c/2 )(C) mg(b/2-a/2)(D) mg(a+c/2-b/2)

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Maximum potential energy is obtained with the brick vertical along side a=mga/2

Minimum potential energy is obtained with the brick vertical along side c=mgc/2

:. Work done=mg(a/2-c/2)

Hence, option (B) is correct.

2843.

What should be the angle between the force and the displacement to get (i) minimum work, (ii) maximum work.

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(i) For minimum work, the angle should be 90°. (ii) For maximum work, the angle should be zero.

2844.

While swimming, state whether the work done bythe force is positive or negative List one moreexample of work done of same nature. Givejustification.

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2845.

1. (a) State the relation between potential difference, work done and charge movedby Calculate the work done in moving a charge or coulombs from a point al 220 volts

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2846.

Two infinite plane parallel sheets, separated bya distance d have equal and opposite unifornmcharge densities σ. Electric field at a Pointbetween the sheets is

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thanks

2847.

define time of flight of projectile

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Aprojectileis an object that is given an initial velocity, and is acted on by gravity. The amount oftimeit spends in the air is called thetime of flight. The unit for thetime of flightis seconds (s).

2848.

Define time of flight of a projectile obtain an expression for it.

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2849.

14. Two infinites parallel have uniform charge densitiesDetermine the electric field in (i)to the left of the sheet, (ii) between them and (iii) to the right of sheets.

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2850.

stions based on High Urve Thinking Skills the33. A piece of wine of resistance 20 drawn out so that its length is increased to twiceCalcular the resistance of the wire in the new situationon

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