CBSE Class 10 Science Board Exam 2017: Solved Question Paper
Jagranjosh brings the CBSE Class 10 Science Solved Question Paper 2017. Here you will get a simple and apt solution for every question which will help you attain the depth with which questions are to be answered while writing the board exams. Download the complete paper in PDF format.
Here we provide you the CBSE Class 10 Science Solved Question Paper 2017. Download the paper from the link given at the end of this article.
Though the structure of this paper is wholly different from that released by the board for Borad Exams 2018, but the importance of questions asked in previous years’ exams cannot be ignored as the syllabus for Class 10 Science remains unaltered. So, studenst must practice the previous years’ papers to get a command over the important topics and prepare accordingly for the CBSE Board Exams 2018.
CBSE Class 10 Science Solved Question Paper 2017, contains:
- 36 question divided into two sections, A and B
- Simple and apt solution for each question
- Every solution framed to match the CBSE Marking Scheme
- Neat and clean diagrams where required
Students need to practice CBSE Class 10 Science Solved Question Paper 2017, to check their preparedness and build confidence for the final exam.
A few sample questions from the CBSE Class 10 Science Solved Question Paper 2017, are given below:
Q. When a cell reproduces, what happens to its DNA?
When a cell reproduces, its DNA gets transferred from parents to the offspring where it gets replicated, producing two copies of DNA. When the cell divides into two, these two copies are distributed equally between the two daughter cells so that similar amount and type of DNA is transferred from the parent cell to the daughter cells.
Q. State two advantages of conserving (i) forests, and (ii) wild-life.
Advantages of conserving forests are:
1. They help in retaining ground water and prevent soil erosion by holding the top layer of soil.
2. They help to prevent floods.
3. They help to improve the quality of air and maintain the moderate temperature.
4. They form a home to a large variety of flora and fauna.
5. They supply raw materials to many industries, like wood, rubber, spices, medicinal herbs, etc.
Advantages of conserving wildlife are:
1. It helps in maitaining ecological balance and biodiversity.
2. It provides food and forms raw material for clothing, medicines and many other products.
Q. Na, Mg and Al are the elements of the 3rd period of the Modern Periodic Table having group number 1, 2 and 13 respectively. Which one of these elements has the (a) highest valency, (b) largest atomic radius, and (c) maximum chemical reactivity? Justify your answer stating the reason for each.
As the elements Na, Mg and Al belong to the same period (3rd period) and group 1, 2 and 13 respectively. Hence the electronic configurations of these three elements can be written as follows:
Sodium, Na (11) = 2, 8, 1
Magnesium, Mg (12) = 2, 8, 2
Aluminium, Al (13) = 2, 8, 3
(a) The element which can lose or gain maximum number of electron will have the maximum valency. Here, Aluminium having configuration 2, 8, 3 will lose all 3 valence electrons to attain stable configuration hence it will have highest valency among all.
(b) As all three elements belong to the same radius in order Na(11), Mg(12), Al(13) and we know that the atomic size decreases on moving from left to right across a period. Therefore the element having the largest atomic radius will be sodium (Na).
(c) The given three elements are metals and we know that the the chemical reactivity of a metal is determined by its metallic character, i.e., its tendency to lose the valence electrons.
Now, the tendency to lose the electrons dereases across the period, i.e., from left to right. So, the element having highest chemical reactivity is sodium (Na).
Q. (a) Write the functions of each of the following parts in a human female reproductive system:
(iii) Fallopian tube
(b) Write the structure and functions of placenta in a human female.
(a) Functions of the Ovary:
(i) It produces female gametes (ova). One ovum is released by one ovary
(ii) It secretes female sex hormones (estrogen and progesterone).
Functions of the Uterus:
(i) It protects and nourishes the developing foetus.
(ii) It provides sufficient space for the growing embriyo.
Functions of Fallopian tube:
(i) It passes down the ovum towards the uterus released by the ovary.
(ii) It acts as the site of fertilisation.
(b) Structure of the placenta in human female:
- Placenta is a disc embedded in the uterine wall which is the connecting link between the mother's body and the baby.
- It contains villi on the embryo’s side of the tissue. The mother’s end of the placenta has
blood spaces which surround the villi.
Functions of placenta in human female:
- Placenta functions as a site of exchange of materials between the blood of mother and foetus.
- It provides a large surface area for glucose and oxygen to pass from the mother to the baby.
- The foetus gives away waste products and carbon dioxide to the mother’s
blood for excretion.
Q. A student focuses the image of a candle flame, placed at about 2 m from a convex lens of focal length 10 cm, on a screen. After that he moves gradually the flame towards the lens and each time focuses its image on the screen.
(A) In which direction does he move the lens to focus the flame on the screen?
(B) What happens to the size of the image of the flame formed on the screen?
(C) What difference is seen in the intensity (brightness) of the image of the flame on the screen?
(D) What is seen on the screen when the flame is very close (at about 5 cm) to the lens?
(A) He moves the lens away from the screen to focus the image.
(B) Size of the image increases.
(C) The intensity of image decreases as the flame moves towards the lens.
(D) No distinct image is formed on the screen as in this case the image formed is virtual which can't be obtained on the screen.
Download the complete CBSE Class 10 Science Solved Question Paper 2017
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