Science 2005 CBSE [ Delhi ] Set II
To Access the full content, Please Purchase
-
Q1
Write the chemical equation for the reaction of hot aluminium with steam. Marks:1View AnswerAnswer:
2Al + 3H2O (g) 
Al2O3 + 3H2 -
Q2
Name a metal which offers higher resistance to the passage of electricity than copper. Marks:1View AnswerAnswer:
Iron -
Q3
Where will the image be formed by a concave mirror when an object is placed between the pole and the focus point of the mirror? Marks:1View AnswerAnswer:
The image will be formed behind the mirror when an object is placed between the pole and the focus point of the concave mirror. -
Q4
Which has a higher resistance: a 50 W lamp bulb or a 25 W lamp bulb and how many times? Marks:1View AnswerAnswer:
A 25 W lamp bulb has a higher resistance and it will be twice than that of the 50 W lamp bulb. -
Q5
Write the expanded form of the abbreviation AIDS. Marks:1View AnswerAnswer:
Out of syllabus. -
Q6
What is 'Green House Effect'? Marks:1View AnswerAnswer:
The phenomenon of trapping of reflected infrared sunrays by gases like carbon dioxide in the atmosphere is called as Green-house effect. -
Q7
Why is much less heat generated in long electric cables than in filaments of electric bulbs? Marks:1View AnswerAnswer:
Long electric cables are made of copper and the filaments of the electric bulbs are made of tungsten. Since the resistivity of the copper is less than that of the tungsten, that's why less heat is generated in long electric cables than in the filaments of the electric bulbs. -
Q8
Name the type of chromosome in which one arm is very long and the other is very short. Marks:1View AnswerAnswer:
Out of syllabus. -
Q9
With respect to air the refractive index of kerosene is 1.44 and that for diamond is 2.42. Calculate the refractive index of diamond with respect to kerosene. Marks:2View AnswerAnswer:
Refractive index of kerosene with respect to air (n1) = 1.44
Refractive index of diamond with respect to air (n2) = 2.42 Refractive index of diamond with respect to kerosene,
n21 =n2/ n1 Or, n21 = 2.42/1.44 Or, n21 = 1.68 -
Q10
How is plaster of Paris chemically different from gypsum? How may they be interconverted? Write one use of plaster of Paris. Marks:2View AnswerAnswer:
Plaster of Paris is calcium sulphate hemihydrate whereas gypsum is calcium sulphate dihydrate. Plaster of Paris can be converted to gypsum by mixing it with water. Gypsum can be converted to plaster of Paris by heating gypsum at 373 K. Plaster of Paris is used to make toys and decorative materials.
