Explore topic-wise InterviewSolutions in Current Affairs.

(a) If half part of a convex lens is covered, the focal length does not change, but the intensity of image decreases.

(b) A convex lens is placed in water. Its focal length will increase.

(c) The focal length of a thin convex lens is more than that of a thick convex lens.

Radius of curvature of convex mirror, R = 30 cm.

Focal length of convex mirror, f=R/2=30cm/2=15cm

Now h=5cm,u=-20cm,v=?,h'=?

Using the mirror formula 1/f=1/u+1/v, we have

1/v=1/f=1/u=1/15=1/-20=1/15+1/20=(4+3)/60

v=60/7=8.6cm.

Thus, image is formed at a distance of 8.6cm behind the convex mirror. The image is virtual and erect.

m=h'/h=-v/u

h'/5=-8.6/(-20)

h'=8.6/20x5=2.15cm.

Thus, the size of the image is 2.15 cm u,which is positive. It indicates that the image formed is erect, virtual and diminished.

(c) virtual, erect and diminished image.

(b) First focus

Lens is made of a transparent material;
Clay is not transparent [choice (d) is correct].

सूचना, भाषण, संगीत आदि को किसी उचित ट्रांसड्यूसर द्वारा विद्युत सिगनल में परिवर्तित किया जाता है। यह सिगनल ही सूचना (संदेश) सिगनल कहलाता है।

अति उच्च आवृत्ति (30 मेगाहर्ट्ज़ से 300 मेगाहर्ट्ज), परा उच्च आवृत्ति (300 मेगाहर्ट्ज से 3000 मेगाहर्ट्ज) तथा 3000 मेगाहर्ट्ज से उच्च आवृत्ति की रेडियो तरंगें आकाश तरंगें कहलाती हैं।

किसी सिगनल में अधिकतम तथा न्यूनतम आवृत्तियों के अन्तर को आवृत्ति परास कहते हैं। यही बैण्ड-चौड़ाई भी कहलाती है।

वह संचरण प्रक्रिया जिसमें वाहक तरंगों का संचरण आयन मण्डल से तरंगों के परावर्तन से होता है, व्योम तरंग संचरण कहलाती है। व्योम तरंगों की आवृत्ति 1.5 मेगाहर्ट्ज से 30 मेगाहर्ट्ज तक होती है।

यह वह क्रिया है जिसमें उच्च आवृत्ति की वाहक तरंगों के आयाम, आवृत्ति अथवा कला को निम्न आवृत्ति के सूचना सिगनल के तात्क्षणिक मानों के अनुकूल परस्पर इनके अध्यारोपण के माध्यम से बदला जाता है ।

वह तरंग संचरण जिसमें आकाश तरंगें प्रेषण ऐण्टीना से अभिग्राही ऐण्टीना तक दृष्टि रेखा पथ पर गमन करती हैं। इन तरंगों का संचरण निम्न दो प्रकार से किया जा सकता है 

1. भू-स्थिर संचार उपग्रहों के द्वारा। 

2. सीधे प्रेषित ऐण्टीना के द्वारा।

1. प्रेषित्र, 

2. संचार चैनल, 

3. अभिग्राही।

The ray of light will bend away from the normal.

(iv) आकाश तरंगों द्वारा

मॉड्यूलन की वह प्रक्रिया जिसमें वाहक तरंग के आयाम को मॉड्यूलक या मॉड्यूलेटिंग तरंग (सूचना संकेत) के तात्क्षणिक मान द्वारा परिवर्तित किया जाता है, जबकि वाहक तरंग के अन्य दो प्राचल आवृत्ति तथा कला अपरिवर्तित रहते हैं, आयाम मॉड्यूलन कहलाती है।

The ray of light bends towards the normal. This is because water is an optically denser medium than air.

ऐण्टीना एक प्रकार का ट्रान्सड्यूसर है जो वैद्युत चुम्बकीय तरंगों को प्रसारित करने या ग्रहण करने के काम आता है। ऐण्टीना की न्यूनतम लम्बाई 75 मीटर होती है जो कि व्यावहारिक है।

मॉड्यूलक तरंग के आयाम तथा वाहक तरंग के आयाम के अनुपात को मॉड्यूलन सूचकांक कहते हैं। यह उस सीमा को प्रदर्शित करता है जहाँ तक वाहक तरंग का आयाम सूचना सिगनल द्वारा परावर्तित होता है।

Due to change in velocity in the medium and to reduce the time taken to travel the same.

The following are some of the distinctive advantages of a computer system over a manual system. 

a. High speed 

b. Accuracy 

c. Reliability 

e. Storage 

d. Versatility

Urea formaldehyde resin is used in making unbreakable dinnerware and decorative laminates.

According to the question; 

Object distance = u; 

Image distance (v) = -10cm; 

Focal length = -15cm; 

By lens formula;

\(\frac1v-\frac1u=\frac1f\)

⇒ \(\frac1{-10}-\frac1u=\frac1{10}\)

⇒ \(\frac1{u}=\frac1{15}-\frac1{10}\)

⇒ \(\frac1{u}=\frac{2-3}{30}-\frac{-1}{30}\)

⇒ \(\frac1{u}=\frac{-1}{30}\)

⇒ u = -30cm. 

Thus, object should be placed 30cm in front of lens. 

Now; 

Height of object h₁= 2cm;

Magnification = \(\frac{h_2}{h_1}=\frac{v}u\)

Putting values of v and u 

Magnification = \(\frac{h_2}{2}=\frac{-10}{-30}\)

⇒ \(\frac{h_2}{5}=\frac{1}{3};\)

⇒ h2 = \(\frac53\) = 1.67

Height of image is 1.67 cm. 

Thus, the image is virtual, diminished, and erect and one-third of the size of object

When a ray of light travels from one medium to another, its speed changes and this change in speed of light causes the bending of light (refraction of light).

A computer system is mainly composed of the following six elements: Hardware: It includes all the physical components of a computer such as, keyboard, mouse, monitor, processor, etc. These can be touched and a user inputs commands through them. Software: It is referred to a set of the programs that enables a computer to perform its tasks or commands given by the user. 

There are following six types of software.

a. Operating System 

b. Utility Programs 

c. Application Software 

d. Language Processors . 

e. System Software 

f. Connectivity Software

People: It constitutes the most important part of a computer system. It basically refers to the individuals or the users who interact with the computer through the use of hardware and software. The following are the people who are involved in a computer system. 

a. System Analysts 

b. Operators 

c. Programmers

Procedures: A series of operations that are executed in a certain manner in order to achieve a desired set of results is known as ‘Procedures’. There are mainly following three types of procedures. a. Hardware-oriented Procedures b. Software-oriented Procedures c. Internal Procedures

Data: The facts that are gathered and entered into a computer system is known as ‘Data’. It may comprise of numbers, text, graphics, etc.

Connectivity: This refers to the manner, in which a computer system is connected to the other electronic devices through telephone lines, microwave transmission, satellite link, etc., is known as ‘Connectivity’.

Here, NQ is parallel to OS. Therefore, NQ is the correct emergent ray.

Q as it has to be parallel to S.

A file is a collection of organised records related to each other.

• Degree of convergence and divergence provided by a lens is called power of the lens. 
• Unit of power of lens is Diopter D. 
• Focal length of lens used by first student is in positive hence it is a convex lens.
• The lens of second student is a concave lens.

p = 1/f 

= 1/0.5

= 2 

Power of lens (first student) =+2 

Power of lens (second student) = -2

The size of the image formed keeps on increasing as the object is brought closer towards the convex lens.

Since the focal length is negative, therefore the lens is concave lens because the focal length of concave lens is negative.

P (in diopter) = \(\frac{1}{f(in\,meters)}\)

F = -50cm = -0.5m (1m = 100cm)

⇒ P = -\(\frac{1}{0.5}\)= -2 D

Hence power of lens is -2 Dioptre.

∠i=0° and ∠r=0°

The two window based accounting packages are: 

(a) Tally 

(b) MS-Excel 

(i) If the lens is cut along the principal axis than there will be no change in the focal length of the lens because the radius of curvature will remain the same, hence the focal length will remain unchanged. 

(ii) If the lens is cut perpendicular to the principal axis than the focal length will change it will be twice the focal length of the original lens because the radius of curvature will increase and R = 2F.

Window based accounting packages are used in recording, classifying and summarising transactions and events which are of financial character and interpreting the results there of. 

If the two lenses are kept in contact than their power is added 

⇒ Power (P) = P₁ + P₂. 

Hence the power of combination is increased which means that the converging capacity is increased. And the focal length is decreased (because focal length is inversely proportional to the power of lens). 

Therefore the ray after refraction will converge at point close to lens than earlier.

Following are the two features of Computerised Accounting: 

(a) It is an accounting information system which deals with transactions which are of financial nature and can be expressed in terms of money. 

(b) Data accuracy and user friendly. 

(c) It is simple and well structured information system defined by professional bodies.

Data Processing is defined as series of actions or operations that convert collection of facts and figures into useful information.

All the heights of objects and images above principal axis are positive and below the axis are negative.

(a) Given

Object distance (u) = -100cm 

Focal length (f) = 50cm

Image distance = v 

By lens formula;

\(\frac1v\,-\frac1u=\frac1f\)

⇒ \(\frac1v\,-\frac1{-100}=\frac1{50}\)

⇒\(\frac1v\,=\frac1{50}-\frac1{100}\)

⇒\(\frac1v\,=\frac{2-1}{100}-\frac1{100}\)

v =100cm 

Hence the image is formed at 100 cm behind the lens. 

Object distance (u) = -100cm 

Focal length (f) = -25cm 

Image distance = v 

By lens formula;

\(\frac1v\,-\frac1u=\frac1f\)

\(\frac1v\,-\frac1{-100}=\frac{-1}{25}\)

\(\frac1v\,-\frac{-1}{25}=\frac1{100}\)

\(\frac1v\,-\frac{-4-1}{-100}=\frac{-5}{100}\)

⇒ v = \(-\frac{100}5\)

⇒ v= -20cm 

1. All distances are measured from optical centre of the lens. 

2. Distances measured along the direction of the incident light are taken as positive. 

3. The distances against the incident light are taken as negative. 

4. The heights measured vertically above the axis, are taken as positive. 

5. The heights measured vertically down the axis, are taken as negative.

Given 

f₁ = 25cm (Focal length of convex lens is positive) 

⇒ f₁ = 0.25m (1m = 100cm)

P (in dioptre) = \(\frac{1}{f(in\,meters)}\)

⇒ Power of convex lens,(F=25 cm) P₁ = \(\frac{1}{f_1}\)

⇒ P₁ = \(\frac{1}{0.25} = \frac{1}{\frac{1}{4}}\)

∴ P₁ = 4 D

f₂ = -10cm (Focal length of concave lens is negative) 

⇒ f₂ = -0.1m (1m = 100cm) 

⇒ Power of the concave lens (F=10 cm), P₂ = \(\frac{1}{f_2}\)

⇒ P₂ = \(-\frac{1}{0.1}=\frac{1}{\frac{1}{10}}\)

∴ P₂ = -10 D. 

Power of combination = P₁ + P₂.

P = 4D – 10D = -6D. 

Lens power of the combination is -6D. Since it is negative therefore the new lens will behave like concave lens having a focal length of 16.6cm.

Following are the two areas in which Computerised Accounting is commonly used. 

(a) Payroll Accounting 

(b) Stores Accounting.

Following are the two differences between Manual Accounting and Computerised Accounting.

Yes, all distances are measured from the optical centre of the lens. Conventionally, the object is placed on the left side of the iens.

Following are the two advantages of Computerised Accounting: 

(a) It provides accounting and statutory reports to the different users. 

(b) It provides the record of accounting information or transactions which have taken place ‘ in an organisation.

Following are the two factors which should be taken into consideration while introducing Computerised Accounting. 

(a) Flexibility: Computerised Accounting system needs to be flexible and capable of adapting to the changes in the business environment and information technology. 

(b) Reliability: Computerised Accounting must be designed to ensure that they do not accept erroneous data or incomplete records. 

Eye donation advertisements are important as :

(i) They make the people aware about the donation of organs after their death.

(ii) Sympathetic nature towards others.

The advantages of computerised accounting are as follows: 

(a) It is less time consuming in preparing financial statements. 

(b) It is more reliable and error-free. 

(c) It requires less man power to prepare accounts of an organisation. 

(d) it is very easy to modify records of accounts. 

(e) it requires less paper work. 

(f) Retrieval of data is very easy in this system

Following are the factors to be considered while introducing Computerised Accounting in a Business Concern. 

(a) Efficiency: Cost effectiveness is an important factor to be considered while introducing Computer Accounting. 

(b) Flexibility: A business concern should be capable of adapting to changes in business environment. Hence the flexibility factor has to be taken into consideration. 

(c) Simplicity: It should be simple and user friendly to introduce in a business organisations.

(d) Reliability: Reliability is another factor to be considered based on accounting principles and procedures while introducing computerised accounting in business. 

(e) User acceptance: User acceptance and involvement is also considered in adopting Computer Accounting.