Which of the following can be used to measure the potential difference ? (A) Ammeter (B) Voltmeter (C) Both (A) & (B) (D) None of these
Dev0000
Asked:
December 2022
Write one equation each for decomposition reactions where energy is supplied in the form of heat and light.
Dev0000
Asked:
December 2022
Oil and fat containing food items are flushed with nitrogen. Why ? (A) To prevent their reduction. (B) To prevent their oxidation. (C) To protect them from insects. (D) To protect them from rodents.
What do you understand by endothermic reactions ? Give one example.
Define the following : (a) Mineral (b) Gangue
Dev0000
Asked:
December 2022
An object is placed at a position in between the main focus (F ) and the optical centre(O) of a convex lens. Draw a ray diagram showing the position, size and nature of the image formed.
A person who is unable to recognize different colours suffers from :
Dev0000
Asked:
December 2022
Identify the most appropriate option in the following : (i) Element with maximum valency : Na, Mg, Al (ii) Smallest atom : Li, Na, K (iii) Most electronegative element : N, O, F (iv) Least metallic element % Li, Be, B
Dev0000
Asked:
December 2022
An atom has electronic configuration 2, 8, 7. To which of the following elements would it be chemically similar ? (Atomic numbers are given in parentheses). (a) N(7) (b) F(9) (c) P(15) (d) Ar(18)
Dev0000
Asked:
December 2022
You must have come across the three 'R's to save the environment : Reduce, Recycle and Reuse. Explain Recycle in detail.
According to you, why noble gases are placed in a separate group ?
Dev0000
Asked:
December 2022
Which of the following elements has twice as many electrons in its second shell as in its first shell ? (A) Oxygen (O) (B) Nitrogen (N) (C) Fluorine (F) (D) Carbon (C)
Dev0000
Asked:
December 2022
What is common name of NaHCO3 ? (A) Zypsum (B) Bleaching Powder (C) Baking Soda (D) Washing Soda
Dev0000
Asked:
December 2022
At the time of sunrise or sunset, the cause of reddening of Sun is due to the scattering of which rays of light ?
Dev0000
Asked:
December 2022
During the burning of a candle, the chemical energy converts into : (A) Heat energy (B) Light energy (C) Both (A) & (B) (D) None of these
What is wave energy ? Explain in brief.
Dev0000
Asked:
December 2022
Write the chemical equation for the following reactions : (a) Iron with steam (b) Calcium with water
Dev0000
Asked:
December 2022
You must have come across the three 'R's to save the environment : Reduce, Recycle and Reuse. Explain Reuse in detail.
Dev0000
Asked:
December 2022
Which of the following element has a total of three shells with four electron in its valence shell ? (A) Silicon (Si ) (B) Aluminium (Al ) (C) Magnesium (Mg) (D) Sodium (Na)
Dev0000
Asked:
December 2022
Which sodium compound is used for removal of permanent hardness of water ? (A) NaHCO 3 (B) NaOH (C) Na 2SO4 (D) Na2CO3 . 10H2O
Dev0000
Asked:
December 2022
A solution showed pH 9. This solution is : (a) Strongly acidic (b) Strongly alkaline (c) Weakly acidic (d) Weakly alkaline