important questions for pre-board 10th class
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English main natalya ka sketch or maths main 8.4 science main electricity, life process and carbon and its compound, magnetic field
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Q. If the sum of first m terms of an AP is 2m2 + 3m, then what is its second term?
Q. Find the value of ‘k’ so that the zeros of the quadratic polynomial 3x2 – kx + 14 are in the ratio 7:6.
Q. Determine whether the following system of linear equation has a unique solution, no solution or infinitely many solution.
4x − 5y = 3
8x − 10y = 6
Q. If the bisectors of adjacent angles P and Q of a parallelogram PQRS intersect at a point O, then find ∠POQ.
Q. Water flows through a circular pipe, whose internal diameter is 2 cm, at the rate of 0.7 m per second into a cylindrical tank, the radius of whose base is 40 cm. By how much will the level of water in the cylindrical tank use in half an hour?
Q. On a straight line passing through the foot of a tower, two points C and D are at distances of 4 m and 16 m from the foot respectively. If the angles of elevation from C and D of the top of the tower are complementary, then find the height of the tower.
Q. The atomic numbers of three elements A, B and C are 12, 18 and 20 respectively. State, giving reason, which two elements will show similar properties.
Q. What is the effect of DNA copying, which is not perfectly accurate, on the reproduction process?
Q. Give reasons for the following:
(a) Arteries are thick walled.
(b) Blood goes only once in one cycle through the heart in fishes.
(c) Plants have low energy needs.
Q. The resistance of a wire of 0.01 cm radius is 10Ω. If the resistivity of the material of the wire is 50 × 10−8 ohm meter, find the length of the wire.
Q. (a) List the parts of the human eye that control the amount of light entering into it. Explain how they perform this function.
(b) Write the function of retina in human eye.
(c) Do you know that the corneal-impairment can be cured by replacing the defective cornea with the cornea of the donated eye? How and why should we organise groups to motivate the community members to donate their eyes after death?
Q. An object of height 2.5 cm is placed at a distance of 15 cm from the optical centre 'O' of a convex lens of focal length 10 cm. Draw a ray diagram to find the position and size of the image formed. Mark the optical centre 'O', principal focus F and height of the image on the diagram.
Q. If the ratio of the sum of the first n terms of two APs is (7n + 1):(4n + 27), then find the ratio of their 9th terms.