Atoms are made up of tiny particles like electrons, protons and neutrons. Electrons revolves around the nucleus of atom and proton and neutrons are situated in the nucleus. Electrons are negatively charged particles and protons are positively charged particles. However, neutrons are neutral.
Dissolved Oxygen is the amount of gaseous oxygen(O2) dissolved in the water. Oxygen enters the water by direct absorption from the atmosphere, by rapid movement, or as a waste product of plant photosynthesis.
Q4. Which among the following elements is a liquid at room temperature?
निम्नलिखित में से कौन सा तत्व कमरे के तापमान पर द्रव रूप में होता है?
White phosphorus is a material made from a common allotrope of the chemical element phosphorus that is used in smoke, tracer, illumination, and incendiary munitions..As an incendiary weapon, white phosphorus is pyrophoric (self-igniting), burns fiercely and can ignite cloth, fuel, ammunition, and other combustibles.
Q6. Alkali metal can
क्षारीय धातुओं का गुण क्या है?
(a) Be highly unstable at room temperature / कमरेकेतापमानपरअतिस्थिर
(b)vaporize at room temperature / कमरेकेतापमानपरवाष्पीकृतहोतीहैं
(c)easily gain electrons / इलेक्ट्रॉन्सकोआसानीसेप्राप्तकरतीहैं
Sulphur dioxide gas contributes to acid rain. Lichens can be used as air pollution indicators, especially of the concentration of sulfur dioxide in the atmosphere.Lichens are plants that grow in exposed places such as rocks or tree bark. They need to be very good at absorbing water and nutrients to grow there.
Q8. An object at rest will remain at rest and an object in motion will remain in motion until and unless it is acted upon by an external force. This is Newton’s
एक वस्तु जब तक स्थिर हैं तब तक वह स्थिर ही रहेगी, और यदि गति में हैं, तो वह गति में ही रहेगी, जब तक उस पर कोई बाह्य बल नहीं लगाया जायेगा| यह न्यूटन का कौन सा नियम है?
Newton’s first law of motion – sometimes referred to as the law of inertia.Newton’s first law of motion is often stated as. An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
Newton’s second law of motion: The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.
Newton’s third law: For every action, there is an equal and opposite reaction.
Q9. What will happen if an object is dropped from a height and there is no air resistance?
क्या होगा यदि कोई वस्तु को ऊँचाई से निचे गिराया जाएं और वहाँ हवा का प्रतिरोध ना हो ?
(a) it will fall with a constant speed and acceleration / वहएकस्थिरगतिऔरत्वरणकेसाथनिचेगिरेगी
(b)its acceleration will increase / उसकात्वरणकमहोजायेगा
(c)Both speed and acceleration will increase / गतिऔरत्वरणदोनोंमेंवृद्धिहोगी
An object is said to be a freely falling body if it is thrown or dropped vertically at an initial velocity and then only gravity affects its motion. The position of any freely falling body is determined by the initial velocity and the initial height.
Q10. Which among the following is an endothermic reaction?
निम्नलिखित में से कौन सी प्रक्रिया एक ऊष्माग्राही अभिक्रिया हैं?
These examples could be written as chemical reactions, but are more generally considered to be endothermic or heat-absorbing processes like melting ice cubes, melting solid salts, evaporating liquid water.
Q11. Name the catalyst used in the conversion of milk into curd.
दूध को दही में बदलने के लिए उपयोग किये जाने वाले उत्प्रेरक का नाम बताइये|
Lactase (Lactobacillus) is the only catalyst used in making of curd from milk. Milk is converted into curd or yogurt by the process of fermentation. Milk consists of globular proteins called casein. The curd forms because of the chemical reaction between the lactic acid bacteria and casein. During fermentation, the bacteria use enzymes to produce energy (ATP) from lactose.
Q12. What does BOD5 refer to?.
BOD5 किससे संदर्भित हैं?
(a) Biochemical Oxygen Demand in 5 days / पांचदिनोंमेंजैवरसायनऑक्सीजनकीमांग
(b) Biochemical Oxygen Demand in 5 hours / पांचघंटोंमेंजैवरसायनऑक्सीजनकीमांग
(c) Biochemical Oxygen Demand in 5 minutes / पांचमिनटोंमेंजैवरसायनऑक्सीजनकीमांग
(d) Biochemical Oxygen Demand in 5 month / पांचमहीनोमेंजैवरसायनऑक्सीजनकीमांग
Biochemical oxygen demand (BOD, also called biological oxygen demand) is the amount of dissolved oxygen needed by aerobic biological organisms to break down organic material present in a given water sample at certain temperature over a specific time period.
Q13. For every action, there is an equal and opposite reaction, is Newton’s.
प्रत्येक किर्या की उसके तुल्य और एक विपरीत प्रतिकिर्या होती हैं, यह न्यूटन का ___नियम है|
Newton’s third law is: For every action, there is an equal and opposite reaction. The statement means that in every interaction, there is a pair of forces acting on the two interacting objects. The size of the forces on the first object equals the size of the force on the second object.
Q14. Which among the following is false about displacement?
निम्नलिखित में से विस्थापन के बारे में कौन सी बात गलत हैं?
(a) It can be negative, positive and zero / यहधनात्मक, ऋणात्मकऔरशून्यहोसकताहैं
(b) Displacement is never greater than Distance/ विस्थापनकभीभीदूरीसेअधिकनहींहोतीहैं
(c) its SI unit is meter / इसकी SI इकाईमीटरहोतीहैं
A displacement is a vector whose length is the shortest distance from the initial to the final position of a point P. It quantifies both the distance and direction of an imaginary motion along a straight line from the initial position to the final position of the point. It can never be negative.
Q15. Release of which among the following is the primary reason for depletion of the ozone layer?
निम्नलिखित में से किसका मुक्त होना ओज़ोन परत के हास होने का प्रमुख कारण है?
When UV radiation hits a CFC molecule it causes one chlorine atom to break away. The chlorine atom then hits an ozone molecule consisting of three oxygen atoms and takes one of the oxygen molecules, destroying the ozone molecule and turning it into oxygen thus leading to ozone layer depletion.