In the figure given below, ABC is a right angled triangle with ÐABC = 90° is
In the figure given below, ABC is a right angled triangle with ÐABC = 90° is
1. Draw a ray diagram to determine the position of image formed of an object placed between the pole and the focus of concave mirror. [1]
2. The power of a lens is +5.5D. What is the focal length and nature of this lens? [11
3. A 14 years old student is not able to see clearly the questions written on a blackboard placed at a distance of 5m from him.
(i) Name the defect of vision, he is suffering from,
(ii) Name the type of lens used to correct this defect. [1]
4. What change in colour is observed when white silver chloride is left exposed to sunlight? What type of chemical reaction is this? [1]
5. A compound ‘X’ is an important ingredient of an antacid. It is also used in fire extinguisher. Identify ‘X’ & write its chemical formula? [11
6. Giving an example to explain thermit reaction. [1]
7. A student performs an experiment to study the magnetic effect of current around a current carrying straight conductor. He reports that,
(i) the direction of deflection of the north pole of a compass needle kept at a given point near the conductor remains unaffected even when the terminals of the battery sending current in the wire are inter changed.
(ii) for a given battery, the degree of deflection of a N-pole decreases when the compass is kept at a point farther away from conductor. Which of the above obseivations of the student is incorrect? Why? [2]
8. What will be observed when the screen is placed,
(i) between the two inverted prism, and
(ii) after the second inverted prism as shown in the figure?
1. (a)The ratio of the base radii of two right circular cones of the same height is 3 : 4. Find the ratio of their volumes.9:16
(b) The ratio of the heights of two right circular cones is 5 : 2 and that of their base radii in 2:5. Find the ratio of their volumes. Ans2:5
(c) The height and the radius of the base of a right circular cone is half the corresponding height and radius of another bigger cone. Find :(i) the ratio of their volumes. (ii) the ratio of their lateral surface areas. Ans 1:8 , 1:4
2. An open cylindrical vessel is made of a metal. The internal diameter is 7 cm, the internal depth is 10 cm and the metal is 5 mm thick. Calculate
(i) the capacity of the vessel (ii) the volume of the metal. Ans: 385,143
1. Two circles touch each other externally at C and AB is a common tangent to the circles. Then, angle ACB=
(a) 60 o (b) 45 o (c) 30 o (d) 90o
2. The length of an arc that subtends an angle of 24o at the centre of a circle with 5 cm radius is
(a) 2π /3 (b) 3π / 2 (c) π /3 (d) 5π /3
3. An observer 1.5 m tall is 28.5 m away from a tower. The angle of elevation of the top of the tower from his eyes is 450. The height of the tower is
(a) 10 m (b) 20 m (c) 30 m (d) 40 m
4. The probability that a randomly chosen number from one to twelve is a divisor of twelve is
(a) 1/12 (b) 1/2 (c) 1/4 (d) 1/6
5. The value of x, for which the points (x,-1), (2,1) and (4,5) lie on a line is
(a) 0 (b) 1 (c) 2 (d) 3
6. The ratio in which the point R (-2/7, -20/7) divides the join of P(-2,-2) and Q(2,-4) is