The Central Board of Secondary Education (CBSE) will conduct the Science board exam for class 10 tomorrow, March 2, 2024. Students can visit the official website of the CBSE to check sample papers and previous year question papers. The papers are available from the year 2019.
The following is a list of important questions with high marking from previous year Science paper.
Q) All the reproductive methods of living organisms are broadly categorised into two types : 1. Asexual reproduction, and 2. Sexual reproduction.
Asexual reproduction involves the participation of a single parent without the formation of gametes, fertilisation and transfer of genetic material. This method is a common means of rapidly increasing offsprings under favourable conditions.
(a) Name the type of fission that occurs in Leishmania and Plasmodium. (b) Write one advantage of sexual mode of reproduction over asexual reproduction. (c) Give reasons why : (i) Colonies of yeast fail to multiply in water but multiply in sugar solution. (ii) Rhizopus individuals do not grow on a dry slice of bread. (c) Name the filamentous structures a student could identify when he collected water from a pond that appeared dark green. How do these organisms multiply ? Explain.
Q) (a) An object is placed in front of a convex lens of focal length f. If the distance of the object from the lens is 2f, draw a ray diagram to show the formation of the image. Write the value of magnification
in this case.
(b) A student has focussed the image of a candle flame on a white screen using a convex lens. The situation is as given below :
Length of the flame = 2 cm
Focal length of the lens = 12 cm
Distance of the flame from the lens = 16 cm
If the flame is perpendicular to the principal axis of the lens, calculate the values of the following :
(i) Distance of the image from the lens
(ii) Length of the image formed
Q) (i) List three points of difference between nervous and hormonal mechanisms for control and coordination in animals.
(ii) How are auxins related with the bending of plant shoot towards unidirectional light ? Explain.
Q) The ability of a medium to refract light is expressed in terms of its optical density. Optical density has a definite connotation. It is not the same as mass density. On comparing two media, the one with the large refractive index is optically denser medium than the other. The other medium with a lower refractive index is optically rarer. Also the speed of light through a given medium is inversely proportional to its optical density.
(i) Determine the speed of light in diamond if the refractive index of diamond with respect to vacuum is 2.42. Speed of light in vacuum is 3×108 m/s. (ii) Refractive indices of glass, water and carbon disulphide are 1.5, 1.33 and 1.62 respectively. If a ray of light is incident in these media at the same angle (say θ), then write the increasing order of the angle of refraction in these media. 1(iii) (A) The speed of light in glass is 2×108 m/s and in water is 2.25×108 m/s.
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