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Name a substance which can be used as an antiseptic as well as disinfectant.

Question: Name a substance which can be used as an antiseptic as well as disinfectant. Solution: Phenol can be used as an antiseptic as well asa disinfectant. 0.2 percent solution of phenol is used as an antiseptic, while 1 per cent of its solution is used as a disinfectant....

Prove that the perpendicular at the point of contact of the tangent to a circle passes through the centre.

Question: Prove that the perpendicular at the point of contact of the tangent to a circle passes through the centre. Solution: Let AB be the tangent to the circle at point P with centre O.To prove: PQ passes through the point O.Construction: Join OP.Through O, draw a straight line CD parallel to the tangent AB.Proof: Suppose that PQ doesn't passes through point O.PQ intersect CD at R and also intersect AB at P.AS, CD ∥ AB, PQ is the line of intersection,ORP = RPA (Alternate interior angles)but a...

A tent is of the shape of a right circular cylinder

Question: A tent is of the shape of a right circular cylinder upto a height of 3 metres and then becomes a right circular cone with a maximum height of 13.5 metres above the ground. Calculate the cost of painting the inner side of the tent at the rate of Rs 2 per square metre, if the radius of the base is 14 metres. Solution: Letrm be the radius of cylindrical base of cylinder of height bym r= 14 m andh1= 3m Curved surface area of cylinder $=2 \pi r h_{1} m^{2}$ $=25 \frac{22}{7} \times 14 \time...

Why are cimetidine and ranitidine better antacids than sodium hydrogen carbonate

Question: Why are cimetidine and ranitidine better antacids than sodium hydrogen carbonate or magnesium or aluminium hydroxide? Solution: Antacidssuch as sodium hydrogen carbonate, magnesium hydroxide, and aluminium hydroxide work by neutralising the excess hydrochloric acid present in the stomach. However, the root cause for the release of excess acid remains untreated. Cimetidine and rantidine are better antacids as they control the root cause of acidity. These drugs prevent the interaction of...

How do antiseptics differ from disinfectants?

Question: How do antiseptics differ from disinfectants? Give one example of each. Solution: Antisepticsand disinfectants are effective against micro-organisms. However, antiseptics are applied to the living tissues such as wounds, cuts, ulcers, and diseased skin surfaces, while disinfectants are applied to inanimate objects such as floors, drainage system, instruments, etc. Disinfectants are harmful to the living tissues. Iodine is an example of a strong antiseptic. Tincture of iodine (2 3 perce...

Two concentric circles are of radii 5 cm and 3 cm, respectively.

Question: Two concentric circles are of radii 5 cm and 3 cm, respectively. Find the length of the chord of the larger circle that touches the smaller circle. Solution: Given: Two circles have the same centreOandABis a chord of the larger circle touching thesmaller circle at C; also,OA=5 cm andOC=3 cm. In $\Delta O A C, O A^{2}=O C^{2}+A C^{2}$ $\therefore A C^{2}=O A^{2}-O C^{2}$ $\Rightarrow A C^{2}=5^{2}-3^{2}$ $\Rightarrow A C^{2}=25-9$ $\Rightarrow A C^{2}=16$ $\Rightarrow A C=4 \mathrm{~cm}...

What is meant by the term ‘broad spectrum antibiotics’?

Question: What is meant by the term broad spectrum antibiotics? Explain. Solution: Antibioticsthat are effective against a wide range of gram-positive and gram-negative bacteria are known as broad spectrum antibiotics. Chloramphenicol is a broad spectrum antibiotic. It can be used for the treatment of typhoid, dysentery, acute fever, pneumonia, meningitis, and certain forms of urinary infections. Two other broad spectrum antibiotics are vancomycin and ofloxacin. Ampicillin and amoxicillin synthe...

Low level of noradrenaline is the cause of depression.

Question: Low level of noradrenaline is the cause of depression. What types of drugs are needed to cure this problem? Name two drugs. Solution: Anti-depressant drugs are needed to counteract the effect of depression. These drugs inhibit enzymes catalysing the degradation of the neurotransmitter, noradrenaline. As a result, the important neurotransmitter is slowly metabolised and then it can activate its receptor for longer periods of time. Two anti-depressant drugs are: (i)Iproniazid (ii)Phenelz...

Solve this

Question: Three containers $C_{1}, C_{2}$ and $C_{3}$ have water at different temperatures. The table below shows the final temperature $T$ when different amounts of water (given in liters) are taken from each container and mixed (assume no loss of heat during the process) The value of $\theta$ (in ${ }^{\circ} \mathrm{C}$ to the nearest integer) is Solution: $(\mathbf{5 0 . 0 0})$ Let $Q_{1}, Q_{2}, Q_{3}$ be the temperatures of container $C_{1}, C_{2}$ and $\mathrm{C}_{3}$ respectively. Using ...

While antacids and antiallergic drugs interfere with the function of histamines,

Question: While antacids and antiallergic drugs interfere with the function of histamines, why do these not interfere with the function of each other? Solution: Specific drugs affect particular receptors. Antacids and anti-allergic drugs work on different receptors. This is the reason why antacids and anti-allergic drugs do not interfere with each others functions, but interfere with the functions of histamines....

Which forces are involved in holding the drugs to the active site of enzymes?

Question: Which forces are involved in holding the drugs to the active site of enzymes? Solution: Either of the following forcescan be involved in holding drugs to the active sites of enzymes. (i)Ionic bonding (ii)Hydrogen bonding (iii)Dipole dipole interaction (iv)van der Waals force...

If the heights of two right circular cones

Question: If the heights of two right circular cones are in the ratio 1 : 2 and the perimeters of their bases are in the ratio 3 : 4, what is the ratio of their volumes? Solution: Given that, $h_{1}: h_{2}=1: 2$ and $2 \pi r_{1}: 2 \pi r_{2}=3: 4$ i.e., $r_{1}: r_{2}=3: 4$ Therefore, The ratios of volume of their cones will be $v_{1}: v_{2}=\frac{1}{3} \pi r_{1}^{2} h_{1}: \frac{1}{3} \pi r_{2}^{2} h_{2}$ $=\left(\frac{r_{1}}{r_{2}}\right)^{1} \times\left(\frac{h_{1}}{h_{2}}\right)$ $\frac{V_{1}...

Define the term chemotherapy.

Question: Define the term chemotherapy. Solution: The use of chemicals for therapeutic effect is called chemotherapy.For example: the use of chemicals in the diagnosis, prevention, and treatment of diseases....

Why should not medicines be taken without consulting doctors?

Question: Why should not medicines be taken without consulting doctors? Solution: A medicine can bind to more than one receptor site.Thus, a medicine may be toxic for some receptor sites. Further, in most cases, medicines cause harmful effects when taken in higher doses than recommended. As a result, medicines may be poisonous in such cases. Hence, medicines should not be taken without consulting doctors....

In the given figure, a triangle ABC is drawn to circumscribe a circle of radius 2 cm

Question: In the given figure, a triangle ABC is drawn to circumscribe a circle of radius 2 cm such that the segments BD and DC into which BC is divided by the point of contact D are, of lengths 4 cm and 3 cm respectively. If the area of △ABC = 21 cm2then find the lengths of sides of AB and AC. Solution: Construction: Join OA, OB, OC, OE AB at E and OF AC at F We know that tangent segments to a circle from the same external point are congruent.Now, we haveAE = AF, BD = BE = 4 cm and CD = CF = 3 ...

The radii of the base of a cylinder and a cone are

Question: The radii of the base of a cylinder and a cone are in the ratio 3 : 4 and their heights are in the ratio 2 : 3. What is the ratio of their volumes? Solution: Letr1andr2be the radii of the base of a cylinder and a cone. The volume of cylinder $V_{1}=\pi r_{1}^{2} h_{1} \ldots \ldots . .(i)$ The volume of cone $V_{2}=\frac{1}{3} \pi r_{2}^{2} h_{2} \ldots \ldots$. (ii) Dividing (i) by (ii), the, we get $\frac{=3 \times\left(\frac{r_{1}}{r_{2}}\right)^{2} \times\left(\frac{h_{1}}{h_{2}}\r...

Name the macromolecules that are chosen as drug targets.

Question: Name the macromolecules that are chosen as drug targets. Solution: The macromolecules chosen as drug targets are carbohydrates, lipids, proteins, and nucleic acids....

An oil funnel of tin sheet consists of a cylindrical portion 10 cm

Question: An oil funnel of tin sheet consists of a cylindrical portion 10 cm long attached to a frustum of a cone. If the total height be 22 cm, the diameter of the cylindrical portion 8 cm and the diameter of the top of the funnel 18 cm, find the area of the tin required. Solution: Letr1andr2(r1r2) be the radii of the ends of the frustum of a cone. Supposelandhbe the slant height and height of frustum of cone. Diameter of top of the frustum $2 r_{1}=18 \mathrm{~cm}$ $r_{1}=9 \mathrm{~cm}$ Diame...

Explain the term target molecules or drug targets as used in medicinal chemistry.

Question: Explain the term target molecules or drug targets as used in medicinal chemistry. Solution: In medicinal chemistry, drug targets refer to the key molecules involved in certain metabolic pathways that result in specific diseases. Carbohydrates, proteins, lipids, and nucleic acids are examples of drug targets. Drugs are chemical agents designed to inhibit these target molecules by binding with the active sites of the key molecules....

Why do we need to classify drugs in different ways?

Question: Why do we need to classify drugs in different ways? Solution: The classification of drugs and the reasons for classification are as follows: (i) On the basis of pharmacological effect: This classification provides doctors the whole range of drugs available for the treatment of a particular type of problem. Hence, such a classification is very useful to doctors. (ii) On the basis of drug action: This classification is based on the action of a drug on a particular biochemical process. Th...

If PT is a tangent to a circle with centre O and PQ is a chord of the circle such that ∠QPT = 70

Question: If PT is a tangent to a circle with centre O and PQ is a chord of the circle such that QPT = 70∘then find the measure of POQ Solution: We know that the radius and tangent are perperpendular at their point of contact.OPT = 90∘Now, OPQ = OPT TPQ = 90∘ 70∘= 20∘Since, OP = OQ as both are radiusOPQ = OQP = 20∘ (Angles opposite to equal sides are equal)Now, In isosceles △POQPOQ + OPQ + OQP = 180∘ (Angle sum property of a triangle)⇒ POQ = 180∘ 20∘ 20∘= 140∘...

Following type of nom-ionic detergents are present in liquid detergents,

Question: Following type of nom-ionic detergents are present in liquid detergents, emulsifying agents and wetting agents. Label the hydrophilic and hydrophobic parts in the molecule. Identify the functional group (s) present in the molecule. Solution: Functional groups present in the molecule are: (i)Ether, and (ii)primary alcoholic group...

If a cone of radius 10 cm is divided into two

Question: If a cone of radius 10 cm is divided into two parts by drawing a plane through the mid-point of its axis, parallel to its base. Compare the volumes of the two parts. Solution: Consider a cone of radius R and height H. Let a cone of height $\frac{\mathrm{H}}{2}$ is cutout from this cone whose base is parallel to the original cone. Now is $\triangle A Q D$ and $\triangle A P C, Q D \| P C$ $\Delta A Q D-\Delta A P C$ $\frac{Q D}{P C}=\frac{A Q}{A P}$ $\frac{Q D}{2}=\frac{H}{\frac{2}{H}}$...

Write the chemical equation for preparing sodium soap from glyceryl oleate and glyceryl palmitate.

Question: Write the chemical equation for preparing sodium soap from glyceryl oleate and glyceryl palmitate. Structural formulae of these compounds are given below. (i) $\left(\mathrm{C}_{15} \mathrm{H}_{31} \mathrm{COO}\right)_{3} \mathrm{C}_{3} \mathrm{H}_{5}-$ Glyceryl palmitate (ii) $\left(\mathrm{C}_{17} \mathrm{H}_{33} \mathrm{COO}\right)_{3} \mathrm{C}_{3} \mathrm{H}_{5}-$ Glyceryl oleate Solution: (i) (ii)...

In the given figure, common tangents AB and CD to the two circle with centres

Question: In the given figure, common tangents AB and CD to the two circle with centres O1and O2intersect at E. Prove that AB = CD Solution: We know that tangent segments to a circle from the same external point are congruent.So, we haveEA = EC for the circle having centre O1andED = EB for the circle having centre O1Now, Adding ED on both sides in EA = EC, we getEA + ED = EC + ED⇒EA + EB = EC + ED⇒AB = CD...

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