4291.  Which among the given alkali metals has highest specific heat -

a

  Rubidium

b

 Lithium

c

 Potassium

d

 Caesium

Answer & Explanation
Answer : Option B
Explanation :
Lithium has the highest specific heat capacity of any solid element.As of its specific heat capacity, the highest of all solids, lithium metal is often used in coolants for heat transfer applications. It belongs to the alkali metal group of chemical elements. Under standard conditions it is the lightest metal & the least dense solid element. Like all alkali metals, lithium is highly reactive & flammable. For this reason, it is typically stored in mineral oil.

4292.  Which among the given pairs of physical quantities have the same dimensions -

a

  Work & Power

b

 Momentum & Power

c

 Work & Energy

d

 Force & Power

Answer & Explanation
Answer : Option C
Explanation :
Work & Energy.The term energy is used to describe the capacity of a system to do work on another system.) have the same dimension & unit as that of Work. Energy of all types and categories (Surface Tension, Kinetic, Potential etc. Both energy & work have the same dimensional formula of M1L 2T –2. In the SI system, both have the same units of Newton meter.

4293.  Among the following iron ores, the highest percentage of iron content is found in-

a

  Limnonite

b

 Haemetite

c

 None of these

d

 Magnetite

Answer & Explanation
Answer : Option B
Explanation :
Haemetite.Hematite, also spelled haematite, heavy & relatively hardoxide mineral, ferric oxide (Fe2O3), that constitutes the most important iron ore as of its high iron content (70 percent) & its abundance. Many of the various forms of hematite have separate names. Its name is derived from the Greek word for 'blood,' in allusion to its red colour. The steel-gray crystals & coarse-grained varieties have a brilliant metallic lustre & are known as specular iron ore; thin scaly types and categories are called micaceous hematite. Much hematite occurs in a soft, fine-grained, earthy form called red ochre or ruddle. Intermediate between these types and categories are compact varieties, often with a reniform surface (kidney ore) or a fibrous structure (pencil ore). Red ochre is used as a paint pigment; a purified form, rouge, is used to polish plate glass. The most important deposits of hematite are sedimentary in origin. The world's largest production (nearly 75 million tons of hematite annually) comes from a sedimentary deposit in the Lake Superior district in North America.

4294.  The name of instrument used to see the distant objects on the Earth is

a

  Compound microscope

b

 Terrestrial telescope

c

 Astronomical telescope

d

 Simple microscope

Answer & Explanation
Answer : Option B
Explanation :
Terrestrial telescope.A telescope assists the eye chiefly in two way by enlarging the visual angle under which a distant object is seen, & so magnifying that object; and, 2nd ly, by collecting, & conveying to the eye, a larger beam of light than would enter the naked organ, so rendering objects distinct & visible which would otherwise be indistinct & or invisible. Terrestrial telescope is a telescope whose eyepiece has one or two lenses more than the astronomical, for the purpose of inverting the image & exhibiting objects erect. It's essential parts are the object glass, or concave mirror, which collects the beam of light, & forms an image of the object, & the eyeglass, which is a microscope, by which the image is magnified. The terrestrial telescope is also known as the spyglass.

4295.  The antiseptic compound present in dettol is

a

  Iodine

b

 Enloroxylenol

c

 Cresol

d

 Biothional

Answer & Explanation
Answer : Option B
Explanation :
Enloroxylenol.The active ingredient in Dettol that confers its antiseptic property is chloroxylenol (C8H9ClO), an aromatic chemical compound.8% of Dettol's total mixture, with the rest composed of pine oil, isopropanol, castor oil soap, caramel & water. Chloroxylenol comprises 4.

4296.  Energy of Ultraviolet rays is great than

a

  Infra–red rays

b

 X–rays

c

 Cosmic rays

d

 Gamma rays

Answer & Explanation
Answer : Option A
Explanation :
Infra–red rays.The electromagnetic spectrum is the name we use when we talk about different types and categories of radiation as a group. All the parts of the electromagnetic spectrum are the same thing - radiation. The parts of the electromagnetic spectrum, arranged from highest energy to lowest, are gamma rays, X-rays, ultraviolet light, visible light, infrared light, microwaves, & radio waves. Radiation is made up of a stream of photons - particles without mass that move in a wave pattern, all at the same speed - the speed of light. Each photon contains a certain amount of energy. The only difference between the parts of the electromagnetic spectrum is the amount of energy the photons contain. Radio waves have the least energy, & gamma rays have the most

4297.  The scientist Who among the following 1st sent electromagnetic waves to distant places is

a

  Heinrich Hertz

b

 Thomas Alva Edison

c

 James Clerk Maxwell

d

 John Logie Baird

Answer & Explanation
Answer : Option B
Explanation :
Thomas Alva Edison.Radio is the transmission of signals through free space by electromagnetic radiation of a frequency significantly belowthat of visible light, in the radio frequency range, from about 30 kHz to 300 GHz. Experiments were undertaken by Thomas Edison & his employees of Menlo Park. These waves are called radio waves. Edison applied in 1885 to the U.S. Patent Office for a patent on an electrostatic coupling system between elevated terminals. The patent was granted as U.S. Patent 465,971 on December 29, 1891. The Marconi Company would later purchase rights to the Edison patent to protect them legally from lawsuits.

4298.  If cream is removed from milk, its density

a

  May increase or decrease

b

 Increases

c

 Remains the same

d

 Decreases

Answer & Explanation
Answer : Option B
Explanation :
Increases.The density of pure fresh milk being on the average 1.86.032, while the density of fat globules is about 0. It follows that the removal of cream will increase the density, while the addition of water will decrease it.

4299.  Air coolers are more suitable for

a

  hot & humid climate

b

 cool & dry climate

c

 hot & dry climate

d

 cool & humid climate

Answer & Explanation
Answer : Option C
Explanation :
hot & dry climate.An air cooler works on the simple principle of evaporation. On the contrary, the temperature of dry air can be dropped significantly through the phase transition of liquid water to water vapor (evaporation), which can cool air using much less energy than refrigeration. It does not yield good results when humidity is high.

4300.  The chemical name of quartz is

a

  Calcium phosphate

b

 Sodium phosphate

c

 Sodium silicate

d

 Calcium oxide

Answer & Explanation
Answer : Option C
Explanation :

4301.  A moving body on Earth ordinarily comes to rest by itself because of the

a

  Conservation of momentum

b

 Law of inertia

c

 Gravity

d

 Forces of friction

Answer & Explanation
Answer : Option D
Explanation :

4302.  Consider the following statements If there were no phenomenon of capillarity 1. It would be difficult to use a kerosene lamp. 2. One would not be able to use a straw to consume a soft drink. 3. The blotting paper would fail to function. 4. The big trees that we see around would not have grown on the Earth. Which of the statement(s) given above are right?

a

  2 and 4

b

 1, 3 and 4

c

 1, 2 and 3

d

 All of these

Answer & Explanation
Answer : Option B
Explanation :

4303.  Sound cannot pass through

a

  vacuum

b

 steel

c

 water

d

 air

Answer & Explanation
Answer : Option A
Explanation :
Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing. Sound also travels through plasma. Sound is a sequence of waves of pressure that propagates through compressible media such as airor water. (Sound can propagate through solids as well, but there are additional modes of propagation). Sound cannot travel through a vacuum as it does not provide the medium to propagate.

4304.  Aspartame is an artificial sweetener sold in the market. It consists of amino acids and provides calories like other amino acids. Yet, it is used as a low-calorie sweetening agent in food items. What is the basis of this use?

a

  Aspartame is several times sweeter than table sugar, hence food items made with small quantities of aspartame yield fewer calories on oxidation

b

 Aspartame is as sweet as sugar but after ingestion into the body, it is converted into metabolites that yield no calories

c

 When aspartame is used in food processing, the sweet taste remains but it becomes resistant to oxidation

d

 Aspartame is as sweet as table sugar but unlike table sugar, it is not readily oxidised in human body due to lack of requisite enzymes

Answer & Explanation
Answer : Option A
Explanation :

4305.  Number of atoms present in one mole of a gas at STP is

a

  6.023 × 1020

b

 6.023 × 1023

c

 6.023 × 10–23

d

 6.023 × 10–20

Answer & Explanation
Answer : Option B
Explanation :
6..023 × 1023 023 x 1023 atoms. A mole of a gas is the amount of a substance containing 6. This is known as Avogadro's number. 1 mole contains the same number of particles as there are in 12 g of carbon-12 atoms by definition. 12 g of carbon-12 atoms = 6.022 x 1023 carbon atoms.



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