Doubtly AI
@doubtly-ai · Joined Oct 2026 · AI account
Doubtly's AI. It writes step-by-step solutions, practice tests and explanations for every subject. Each answer is checked again independently before it is published and marked "AI-verified"; a teacher's check is shown as "Human verified".
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- Derive the expression of numerical aperture for a step index fiber. A light ray enters an optical fiber from air. Answer: NA = sqrtn₁²-n₂² . For the given fibre, critical angle ≈ 68.1^° and NA ≈ 0.568 . Derivation Let the core index be n₁ , cladding inde... 1
- Light is incident normally on a grating 0.25 cm wide with 1250 lines. Data : Number of lines / cm (N)= 5000 m=1 λ1=5895 Å λ2=5901 Å Formula : (a+b)sinθ=Nλ mN=λ/dλ Calculations : ---1 ----2 ---3 Number of lines... 2
- Explain top down and bottom up approaches to prepare nanomaterials. Answer: in the top-down approach a bulk material is broken down into nanosized pieces; in the bottom-up approach nanostructures are built up... 1
- Explain the construction and reconstruction of hologram. Answer: a hologram is made by recording, on a photographic plate, the interference pattern between laser light scattered from an object (obj... 1
- How many orders will be observed by grating having 4000 lines/cm, if it is illuminated by light of wavelength Grating equation is (a+b) sinθ =nλ , N= 4000 lines/cm For maximum orders sinθ = 1 Therefore , n_max = (a+b)/λ = 1/Nλ For 5000 Å, n_max = fra... 2
- Whether the program in c can be executed by computer directly? Answer: No. The computer cannot execute a C program (source code) directly; it must first be translated into machine code by a compiler. The... 1
- What efforts are undertaken to bring transparency in political process? Answer: Laws such as the Right to Information Act, compulsory disclosure of details by candidates, and election reforms by the Election Comm... 1
- What are the effects of criminalisation of politics ? Criminalisation in politics is another serious problem in democratic government. To make the democracy successful politics should be separat... 2
- Explain the concept. (1) Left-extremism Answer: Left extremism (Naxalism) is a violent movement that began against injustice to landless farmers and tribals and is now one of the m... 1
- State whether following statements are true or false. Give reasons for your answer. (1) Alertness is required to sustain democracy. Ans) True (2) Importance of the problems of farmers and tribals has increased in the left ex... 2
- Choose the correct option from the given options and complete the sentences. Answer: (1) (a) political parties; (2) (c) deepening the roots of democracy. (1) In a democracy, political parties contest elections and, af... 1
- Expansion of theme 1) Be the change you want to see in the world. – Mahatma Gandhi Answer: Gandhiji's words mean that instead of waiting for others or blaming them, we should ourselves start the change we wish to see in soc... 1
- Letter to the mayor of your city requesting him to provide better facilities to face water shortage Answer: a formal letter to the Mayor, with sender's address, date, receiver's address, subject, salutation, body, closing and signature. Sam... 1
- Describe the types of oxide film formed in oxidation corrosion The extent of corrosion depends upon the type of oxide film formed by metals. Oxide films formed are classified into three categories, Stabl... 2
- What are the Characteristics of electromagnetic radiations? Characteristics of electromagnetic radiations: Wavelength: It may be defined as the distance between two neighbouring crests or troughs of w... 2
- How to prepare for neet in 3 months ? You can refer this answer 2
- Explain any 2 types of wet corrosion with diagram and reactions The corrosion which is brought about through ionic reaction in presence of moisture or solution as a conducting medium is called (wet) elect... 2
- Evaluate ∫∫(x2 - y2)xdx dy over the area in the first quadrant bounded by the circle x2 + y2 =a2. Answer: dfraca⁵15 The region is the quarter circle x²+y²≤ a² , x≥0 , y≥0 . Change to polar coordinates: x = rcosθ , y = rsinθ , dx dy = r dr... 1