RRB JE Stage-II Physics Quiz : 24th June

Q1. An isolated thermodynamic system executes a process, choose the correct statements of the following.
एक पृथक थर्मोडायनामिक प्रणाली एक प्रक्रिया को निष्पादित करती है, निम्नलिखित में से सही कथन चुनें।
(a) Heat is transferred/ हीट ट्रांसफर कर दिया जाता है
(b) Work is done/ कार्य किया जाता है
(c) Mass flow across the boundary of the system/ प्रणाली की सीमा के पार बड़े पैमाने पर प्रवाह
(d) chemical reaction takes place within the system/ प्रणाली के भीतर रासायनिक प्रतिक्रिया होती है

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Ans.(d)
Sol. An isolated system is a thermodynamic system that cannot exchange either energy or matter outside the boundaries of the system. There are two ways in which this may occur:
The system may be so distant from another system that it cannot interact with them. The system may be enclosed such that neither energy nor mass may enter or exit.

Q2. The phenomenon of mirage occurs due to which one of the following?
मृगतृष्णा की घटना निम्न में से किसके कारण होती है?
(a) Polarization of light / प्रकाश का ध्रुवीकरण
(b) Dispersion of light / प्रकाश का फैलाव
(c) Diffraction of light / प्रकाश का विवर्तन
(d) Total internal reflection of light /

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Ans.(d)
Sol. A mirage is an optical phenomenon that creates the illusion of water and results from the refraction of light through a non-uniform medium. Mirages are most commonly observed on sunny days when driving down a roadway. Total internal reflection is responsible for mirage formation in deserts.

Q3. Which one of the following common devices works based on the principle of mutual induction?
पारस्परिक प्रेरण के सिद्धांत के आधार पर निम्नलिखित में से कौन सा सामान्य उपकरण काम करता है?
(a) Tube light/ ट्यूब लाइट
(b) Transformer / ट्रांसफार्मर
(c) Photodiode / फोटोडायोड
(d) LED / एलईडी

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Ans.(b)
Sol. A transformer consists of two electrically isolated coils and operates on Faraday’s principal of “mutual induction”, in which an EMF is induced in the transformers secondary coil by the magnetic flux generated by the voltages and currents flowing in the primary coil winding.

Q4. Television signal cannot be received generally beyond a particular distance due to
टेलीविज़न सिग्नल आमतौर पर किसी विशेष दूरी के कारण प्राप्त नहीं किया जा सकता है
(a) Curvature of the Earth / पृथ्वी की वक्रता
(b) Weakness of antenna / एंटीना की कमजोरी
(c) Weakness of signal / संकेत की कमजोरी
(d) Absorption of signal in air / हवा में संकेत का अवशोषण

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Ans.(a)
Sol. Curvature of the earth does not allow the television signals to be received beyond a particular distance.

Q5. If a small raindrop falls through air
यदि एक छोटी सी वर्षा की बूँद हवा से हो कर गिरती है
(a) Its velocity goes on increasing / इसका वेग बढ़ता ही जाता है
(b) Its velocity goes on decreasing / इसका वेग कम होता चला जाता है
(c) Its velocity goes on increasing for some time and then becomes constant / इसका वेग कुछ समय के लिए बढ़ता रहता है और फिर स्थिर हो जाता है
(d) It falls with constant speed for some time and then its velocity increases / यह कुछ समय के लिए निरंतर गति के साथ गिरता है और फिर इसका वेग बढ़ जाता है

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Ans.(c)
Sol. The velocity of a raindrop increases initially due to gravity, but the air drag slows it down. When the two forces (gravity and air resistance) balance, the drop reaches its terminal velocity and falls at that speed till it reaches the ground.

Q6. Consider the following statements
निम्नलिखित कथनों पर विचार करें
X-rays / एक्स-रे
1. Can pass through aluminum. / एल्यूमीनियम से गुजर सकती हैं
2. Can be deflected by magnetic field. / चुंबकीय क्षेत्र द्वारा विक्षेपित किया जा सकता है
3. Move with a velocity less than the velocity of ultraviolet ray in vacuum. / निर्वात में पराबैंगनी किरण के वेग से कम वेग के साथ चलते हैं
(a) 1, 2 and 3 /1,2 और 3
(b) Only 1 /केवल 1
(c) 2 and 3 /2 और 3
(d) 1 and 2 /1 और 2

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Ans.(b)
Sol. X-rays cannot be deflected by magnetic field as they consist of no charge.

Q7. Which one of the following is the permissible level of noise in a silent zone at day time?
निम्नलिखित में से कौन सा एक मौन क्षेत्र में दिन के समय शोर का अनुमेय स्तर है?
(a) 50 dB
(b) 60 dB
(c) 65 dB
(d) 75 dB

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Ans.(a)
Sol. The permissible levels for noise exposure for silence zone area have been prescribed under the Model Rules of the Factories Act, 1948 and the permissible level is 50 dB.

Q8. By which one of the following, an old written material which cannot be read easily, can be read
किसके द्वारा निम्नलिखित में से एक, पुरानी लिखित सामग्री जिसे आसानी से पढ़ा नहीं जा सकता है उसे पढ़ा जा सकता है ?
(a) γ-rays / γ-किरणें
(b) X-rays / एक्स-रे
(c) IR-rays / IR- किरणें
(d) Radiofrequency waves / रेडियोफ्रीक्वेंसी तरंगें

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Ans.(c)
Sol. Infrared rays helps in reading an old written material.

Q9. Earthquake (shock) waves are
भूकंप (झटके) ___________ तरंगें हैं
(a) Infrasonic waves / इन्फ्रासोनिक तरंगें
(b) Ultrasonic waves / अल्ट्रासोनिक तरंगें
(c) Seismic / भूकंपी
(d) Infrared waves / इंफ्रारेड तरंगें

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Ans.(c)
Sol. An earthquake releases energy as shock waves, the so-called seismic waves, which ripple across the earth’s surface. The seismic waves created as they move from the epicenter an earthquake vary. An Earthquake is the result of a sudden release of energy in the Earth’s crust that creates seismic waves.

Q10. Laser is a device to produce
लेज़र ________ उत्पादन के लिए एक उपकरण है
(a) A beam of white light / सफेद रोशनी की किरण
(b) Coherent light / सुसंगत प्रकाश
(c) Microwaves / माइक्रोवेव
(d) X-rays / एक्स-रे

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Ans.(b)
Sol. A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. Lasers can also have high temporal coherence, which allows them to emit light with a very narrow spectrum, i.e., they can emit a single color of light. A laser is a device that emits coherent light through a process called stimulated emission.