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10 Science Solved Sample Paper 3 – Page 3

#### Question: 10. Name three different glands associated with the digestive system in humans. Also name their secretions. 

Answer: These glands and their secretions are:

1. Salivary gland: Its secretion is Saliva
2. Liver: It secretion is called Bile juice
3. Pancreas: Its secretion is Pancreatic juice.

#### Question: 12. A convex mirror used for rear view on an automobile has a radius of curvature of 2 m. If a truck is located at 5 m from the mirror, find the position, nature and size (magnified or diminished) of the image. 

Answer: Convex mirror, R = 2 m   ⇒    f  = 2/2 = +1 m;       u = -5 m,        v = ?
1/v + 1/u = 1/f            ⇒        1/v = 1/f – 1/u             ⇒          1/v = 1/1 – 1/-5
⇒       1/v = 5+1/5 = 6/5       ∴        v = 5/6 = 0.8 m.
⇒       m = –v/u = -0.8/-5.0 = 0.16 (image is erect, virtual and diminished)

#### Question: 13. What is a wind mill? Write two advantages and two limitations of using wind mills to generate electricity. 

Answer:  Wind mill is a device which uses the wind energy (kinetic energy of wind) to generate electrical energy.

#### Question: 14. The electronic configuration of an element ‘X’ is 2, 8, 8, 2.Write its (1). group number, (2). period number and  (3). the number of valence electrons in its atom. Justify your answer in each case. 

Answer: X = 2, 8, 8, 2 ⇒ (1). Group number = 2nd; (2). Period number = 4; (3). Valence electrons = 2

#### OrAn element ‘X’ has atomic number 6. Another element ‘Y’ has 17 electrons in its neutral atom.(1). To which group of modern periodic table do ‘X’ and ‘Y’ belong?(2). What type of bond will be formed in the compound when ‘X’ and ‘Y’ combine?(3). Write the formula of this compound. State reason for your answer in each case.

Answer: X = 2, 4; Y = 2, 8, 7

1. X belongs to 4th group, Y belongs to 7th group;
2. Covalent bond;
3. XY4

#### Question: 15. Mendel crossed a tall pea plant producing round seeds and a short pea plant producing wrinkled seeds. Write the plant type of F1 and F2 progenies he got and the plant conclusion he had drawn from such a cross.

Hint: Law of Independent Assortment and Dihybrid Inheritance.
F1: all plants were tall with round seeds.