Engrumair@yahoo.com XI PHYSICS TARGET PAPER OF FOR 2023 SHORT QUESTIONS Q .Prove F = F 1 2 + F 2 2 +2F 1 F 2 Cos 𝜃 Q.Define Linear momentum OR Angular momentum State and prove it. Q. Prove a c = V 2 /r, v = r ω Q.What is Weighlessness. How the aritifici al gravity created in satellite? Derive relevant expression. Q.Find the value of “g” with altitude OR Depth ? Q. Derive work energy equation. Q. What are the laws of transverse waves ?Derive expression for the fundamental frequency and harmonics Q.Derive the expression for the energy and power transmitted through waves. Q.Describe Newton’s formula for the speed of sound?How did Laplace correct it? W hat is effe ct of temperature on sound? Q.Define SHM.Prove it wiht the help of simp le pendulum. Q.What is the difference b/w fresnal and fraunhofer diffraction? Derive Bragg’s law. Q. Difference b/w Spherical and chromatic abbriation. Derive the formula 1/f = 1/f 1 + 1/f 2. DETAIL QUESTIONS Q. Define Dot and cross product.Prove A.(B+C) = A.B +A .C , A x B = - B x A and ( A B ) 2 + ( A × B ) 2 = ( AB ) 2 , A. B = B.A Q.Tension in a string both cases Q .Define Projectile motion.Discuss its all cases Q.State and prove Law of conservation of energy. Q Derive the expressions for AGPE. Q.Show that the motion of particle moves in circle execute SHM.Aslo derive the formula for the instantaneous velocity. Q .Show the total energy of a body attached to an elastic spring and executing S.H.M remains same. Q.Describe Newton’s formula for the speed of sound?How did Laplace correct it? W hat is effect of temperature on sound? Q.What is Dop p ler’s effect and its 3 application.Discuss its cases. Q. Describe Newtons’ rings. Derive the relevan t ex pression OR Diffraction gra ting with relevant expression. Q .Describe the cons truction and working of simple microscope OR compound micro s cope . NUMERICALS Chp #2 Pb: 8,12 ,16,20,22. Exp.9,12. Chp#3 Pb: 2,4, 5,9, 10, 11,12 ,13 , 15. Exp.2. Chp#4 Pb: 2,4,6,8,10,11,12 Exp. 6,7. Chp#5 Pb: 4,5, 6, 10. Exp.5 Chp#6 Pb: 2,4,5,6 ,9 Exp 6.2 Chp#7 Pb .4 ,5,6 ,8 Chp#8 Pb: 2,4,6, 9,10. Exp. 2,3, 5 Chp#9 Pb: 1,2,4,6,7,8 Exp.1 Chp#10 Pb: 3,6,7, 9,10,12,13. Exp 6 Note: Red color shows most important questions ************************************* BEST OF LUCk *********************************** XI PHYSICS PRACTICE PROBLEMS CHAPTER # 02 1. A = i + j + K and b =2 i - j + 3 k , f ind a u n i t v ect o r pa r a l l e l t o A - 2 B Ans : - 4.9i+4.5j - 7.63k 2. If two vectors 𝐴 ⃗ and 𝐵 ⃗ ⃗ such that 𝐴 ⃗ = 3, 𝐵 ⃗ ⃗ = 2 and 𝐴 ⃗ - 𝐵 ⃗ ⃗ = 4 then evaluate 𝐴 ⃗ + 𝐵 ⃗ ⃗ Ans 3.16 3. Find the value of P for which the following vectors are perpendicular to each other A=i+pj+3k, B=3i+3j - 4k. Ans 3 4. Two forces of magnitude 10 N and 15 N are acting at a point.The magnitude of their resultant is 20N, find the angle b/w them Ans 75.2 o 5. T w o f o rces o f e qu a l m a gni t ud e a r e a c t i n g a t a poin t F i nd t h e a ngl e b e tw e e n t h e f o r ces a n d t h e m agn i t u d e o f t h e r e s u l t a n t i s a l s o e q u al t o t h e m a g ni t ud e o f e i t h e r o f t h e s e f o rce s Ans 120 o 6. If one of the rectangular components of a force of 50N is 25N,find the value of other. 7. Prove that the vectora A = - 4 i + K, b =3 i + j + 2 k and i - j - k can form the three sides of a triangle. CHAPTER # 03 1. A 12kg gun mounted on wheels shoots a 100gm projectile with a muzzle velocity of 1800m/s at an angle of 60° above the horizontal , find the horizontal recoil velocity of the gun. Ans: 7.5 m/s 2 A boy throws a ball vertically upward with a speed of 25m/s. On its way down, it is caught at a point 5m above the ground. Ho w fast was it coming down at this point? How long did th e trip take? Ans 22.9m/s, 4.89s 3 A stone is dropped from the peak of a hill. It covers a distance of 30 meters in the last second of its motion. Find the heig ht of the peak. Ans 62.1 m 4 A 100gm golf ball moving with a velocity of 20m/s collides with a 8kg steel ball at rest. If the collision is elastic, comput e the velocities of both balls after the collision. Ans - 19.5m/s, 0.49m/s 5 A rickshaw driver moving with a speed of 36km/h, notice a child standing in the middle of the road and bring his rikshaw to rest in 4sec just in time to save the child. What the average retarding force on the rikshaw? The mass of the rikshaw is 400kg and th e mass of the driver is 65kg. Ans - 1162.5 N CHAPTER # 04 1. A rocket is fired at a ground - level target 600m away with an initial velocity 85 m/s . Find two possib le values of the launch angle. Calculate the minimum time to hit the target. [27.2 ° , 62 8° , 7 93 𝑠 ] 2. At what suitable angle is the maximum height of the projectile 1/3 of its range? Ans: 53.1 o 3. A bullet was fired horizontally with 20m/s from the top of a building 20m high. When the bullet was 10m above the ground, it incidentally hits a bird. Find the time taken to hit the bird and the velocity of bullet when it hits the bird. Ans 1.42s, 24.4m/s 4. Show that R max = 4H max 5. When an aircraft is moving is moving in a horizontal plan at a constant speedof 650 m/s and its turning circle has radius of 80 km. What is the ratio of the centripe tal force to the wight of the aircraft. Ans: 0.53 6. A string 1m long would break when its tension is 69.6N. Find the greatest speed at which a ball of mass 2kg can be whirled wi th the string in a vertical circle. Ans: 5.9m/s CHAPTER # 0 5 1. A wooden ball of mass 100gm is suspended by a thread. The horizontal current of air blows it to one side such that the thread makes an angle of 30 ° with the vertical; find the tension in the thread and the force of air current. Ans: 1.24 N, 2.66N CHAPTER # 06 1. At what depth from the surface of the earth is the value of acceleration due to gravity one - fourth the value of the earth surface? Ans: 0.75 Re 2. Suppose a new planet X is discovered which has a diameter 10yimes bigger as compared to that of e arth and mass equal to 300 times that of earth. Compute the gravitational acceleration at the surface of the planet X. Ans: 3g 3. Ratio of the acceleration due to gravity inside the deep mine and that on the surface of earth is 0.99. Find the depth of the min e,assuming that the density of earth is is uniform throughout and the radius of earth is 6300 km. Ans: 63800m 4. How many times in a second a spaceship of diameter 30 meters to be rotated in order to create the similar gravity as experienced on earth. Ans 0.12 times CHAPTER # 08 1. Find the length of second’s pendulum on planet Jupiter where the value of “g” is 2.63 times that of the “g” at the surface of earth. Ans: 2.61m 2. A simple pendulum completes 4 vibrations in 8 sec on the surface of earth. Find the time the time period on the surface of th e moon where the acceleration due to gravity is one - sixth that of the earth Ans: 5 s 3. Find the speed of sound in ai r at 5 0 0 and 75 0 (take speed of sound at 332m/s) Ans: 4. Find the velocity of sound in a gas when tow waves of length 0.8m and 0.81 respectively, produce 4 beats per second Ans: 266.6m/s 5 . A note of frequency 650Hz emitted from an ambulance . What freq uency will be detected by a listener if the ambulance moves with (i) the speed of 18 m/s towards the listener (ii) At the speed of 15 m/s away from the listener (Speed of sound = 340 m/s) Ans: 686.33Hz, 622.5 Hz. 6. A note of frequency 500Hz being emitted by an ambulance moving towards a listener at rest. If the listener detects a frequenc y of 526Hz, Calculate the speed of the ambulance. Take the speed of the sound at room temperature to be 340 m/sec . Ans: 16. 8m/s 7. A source of sound and a listener are moving towards each other with velocities which are 0.5 times and 0.2 times the speed of sound respectively. If the source is emitting 2KHz tone. Calculate the frequency heard by the listener. Ans: 800 Hz 8. Two cars are moving straight to each other from opposite directions with same speed. The horn of one is blowing with the frequency of 3000Hz and is heard by the people in the other car with the frequency of 3400Hz; find the speed of the cars if t he spe ed of the sound in air is 340m/s. Ans: 21.2m/s CHAPTER # 10 1. The magnifying power of a magnifying glass is 6. What is the power of lens in dioptres? What is the best position of the obj ect if a watch maker holds the same magnifying glass close to his eye to see the damaged spring of the watch? Ans = 20D, 4.16cm 2. An astronomical telescope has a length of 105 cm and its magnification is 6.Determine the power of objective and eye piece? Ans: 1.1 di o,6.66dio 3. A magnifying glass of focal length 6cm is used to see a small specimen. The least distance of distinct vision of the observer is 25cm. What is the magnifying power of the lens? Ans: 5.16