Q1. A fan produces feeling of comfort during hot weather, because-
एक पंखा गर्म मौसम के दौरान आराम का अहसास करवाता है, क्योंकि-
(a) fan supplies cool air / पंखा ठंडी हवा की आपूर्ति करता है
(b) our perspiration evaporates rapidly / हमारा पसीना तेजी से वाष्पित होता है
(c) Our body radiates more heat in air / हमारा शरीर हवा में अधिक गर्मी फैलाता है
(d) conductivity of air increases / वायु की चालकता बढ़ जाती है
Q2. The technique used to transmit audio signals in television broadcast is-
टेलीविज़न प्रसारण में ऑडियो सिग्नल संचारित करने के लिए किस तकनीक का इस्तेमाल होता है -
(a) Amplitude modulation/आयाम मॉड्यूलन
(b) Pulse code modulation/पल्स कोड मॉडुलेशन
(c) Frequency modulation/आवृति मॉडुलेशन
(d) Time dimension multiplication/समय आयाम बहुलीकरण
Q3. Bats can fly during dark nights and also prey. This is because-
चमगादड़ रात के अँधेरे के दौरान उड़ान भर सकते हैं और शिकार भी कर सकते हैं. यह है क्योंकि-
(a) The pupil of their eyes is large / उनकी आंखों की पुतली बड़ी होती है.
(b) Their night vision is very good / उनकी रात्रि दृष्टि बहुत अच्छी है
(c) Every bird can do this / प्रत्येक पक्षी यह कर सकता है.
(d) They produce ultrasonic waves and are guided by them / वे अल्ट्रासोनिक तरंगें पैदा करते हैं और इनके द्वारा निर्देशित होते हैं
Q4. Which one of the following is the effect of the flight of supersonic jet?
निम्नलिखित में से क्या सुपरसोनिक जेट की उड़ान का प्रभाव है?
(a) Air pollution/वायु प्रदुषण
(b) Eye disease/नेत्र रोग
(c) Depletion in ozone layer/ओजोन परत में कमी
(d) None of these/इनमे से कोई नहीं
Q5. Which of the following has the longest wavelength?
निम्नलिखित में से किसकी सबसे लंबी तरंग दैर्ध्य है?
(a) Infrared/इन्फ्रारेड
(b) X-rays/एक्स-रे
(c) Visible light/दृश्य प्रकाश
(d) Radio waves/ रेडियो तरंगें
Q6. A radio station broadcast at 30 metre band. The frequency of the carrier wave transmitted by this station is:-
एक रेडियो स्टेशन 30 मीटर बैंड पर प्रसारण करता है. इस स्टेशन द्वारा प्रेषित वाहक तरंग की आवृत्ति कितनी होती है:-
(a) 10 KHz /10 किलोहर्ट्ज
(b) 100 KHz / 100 किलोहर्ट्ज
(c) 10 MHz /10 मेगाहट्र्ज
(d) 100 MHz/ 100 मेगाहट्र्ज
एक पंखा गर्म मौसम के दौरान आराम का अहसास करवाता है, क्योंकि-
(a) fan supplies cool air / पंखा ठंडी हवा की आपूर्ति करता है
(b) our perspiration evaporates rapidly / हमारा पसीना तेजी से वाष्पित होता है
(c) Our body radiates more heat in air / हमारा शरीर हवा में अधिक गर्मी फैलाता है
(d) conductivity of air increases / वायु की चालकता बढ़ जाती है
Show Answer
S1 Ans.(b)
Sol. In summer, a ceiling fan in the counterclockwise direction can help to cool your home by pushing cool air down. During the hot summer months, though this wind chill effect can work to your advantage by providing a breeze that can help evaporate the skin’s moisture quickly, creating a cool feeling.
Sol. In summer, a ceiling fan in the counterclockwise direction can help to cool your home by pushing cool air down. During the hot summer months, though this wind chill effect can work to your advantage by providing a breeze that can help evaporate the skin’s moisture quickly, creating a cool feeling.
Q2. The technique used to transmit audio signals in television broadcast is-
टेलीविज़न प्रसारण में ऑडियो सिग्नल संचारित करने के लिए किस तकनीक का इस्तेमाल होता है -
(a) Amplitude modulation/आयाम मॉड्यूलन
(b) Pulse code modulation/पल्स कोड मॉडुलेशन
(c) Frequency modulation/आवृति मॉडुलेशन
(d) Time dimension multiplication/समय आयाम बहुलीकरण
Show Answer
S2. Ans.(c)
Sol. Television broadcasts emit two types of signals, audio and visual. These two signals require modulation to transmit both signals at the same time. Analog television requires transmission that uses specific modulation methods employing AM and FM signals in its transmission. Frequency modulation or FM is used for the audio part of the transmission. Amplitude modulation or AM is used in the video transmission.
Sol. Television broadcasts emit two types of signals, audio and visual. These two signals require modulation to transmit both signals at the same time. Analog television requires transmission that uses specific modulation methods employing AM and FM signals in its transmission. Frequency modulation or FM is used for the audio part of the transmission. Amplitude modulation or AM is used in the video transmission.
Q3. Bats can fly during dark nights and also prey. This is because-
चमगादड़ रात के अँधेरे के दौरान उड़ान भर सकते हैं और शिकार भी कर सकते हैं. यह है क्योंकि-
(a) The pupil of their eyes is large / उनकी आंखों की पुतली बड़ी होती है.
(b) Their night vision is very good / उनकी रात्रि दृष्टि बहुत अच्छी है
(c) Every bird can do this / प्रत्येक पक्षी यह कर सकता है.
(d) They produce ultrasonic waves and are guided by them / वे अल्ट्रासोनिक तरंगें पैदा करते हैं और इनके द्वारा निर्देशित होते हैं
Show Answer
S3. Ans.(d)
Sol. Bats are fascinating group animals. They are one of the few mammals that can use ultrasonic sound to navigate. As they fly, make an ultrasonic (shouting) sound. The returning echoes give the bats information about anything that is ahead of them, including the speed and size of an insect and which way it is going. This system of finding prey is called echolocation-locating things by their echoes.
Sol. Bats are fascinating group animals. They are one of the few mammals that can use ultrasonic sound to navigate. As they fly, make an ultrasonic (shouting) sound. The returning echoes give the bats information about anything that is ahead of them, including the speed and size of an insect and which way it is going. This system of finding prey is called echolocation-locating things by their echoes.
Q4. Which one of the following is the effect of the flight of supersonic jet?
निम्नलिखित में से क्या सुपरसोनिक जेट की उड़ान का प्रभाव है?
(a) Air pollution/वायु प्रदुषण
(b) Eye disease/नेत्र रोग
(c) Depletion in ozone layer/ओजोन परत में कमी
(d) None of these/इनमे से कोई नहीं
Show Answer
S4. Ans.(c)
Sol. A jet engine is a machine for turning fuel into thrust. The thrust is produced by action and reaction also known as Newton’s third law of motion. Those jet planes which are able to fly faster than the speed of sound are called supersonic jet planes. Jet engines are responsible for depletion of ozone. Flying at stratosphere height, they emits nitrogen oxide which has the potential to destroy significant quantities of ozone in the stratosphere.
Sol. A jet engine is a machine for turning fuel into thrust. The thrust is produced by action and reaction also known as Newton’s third law of motion. Those jet planes which are able to fly faster than the speed of sound are called supersonic jet planes. Jet engines are responsible for depletion of ozone. Flying at stratosphere height, they emits nitrogen oxide which has the potential to destroy significant quantities of ozone in the stratosphere.
निम्नलिखित में से किसकी सबसे लंबी तरंग दैर्ध्य है?
(a) Infrared/इन्फ्रारेड
(b) X-rays/एक्स-रे
(c) Visible light/दृश्य प्रकाश
(d) Radio waves/ रेडियो तरंगें
Show Answer
S5. Ans.(d)
Sol. The electromagnetic spectrum consists of all the different wavelength of electromagnetic radiations such as: Radiowaves > Microwave > Infrared > Visible > Ultraviolet > X-rays > Gamma rays. Thus it is clear that the radio-waves are having the maximum wavelength while the Gamma rays are having minimum wavelength.
Sol. The electromagnetic spectrum consists of all the different wavelength of electromagnetic radiations such as: Radiowaves > Microwave > Infrared > Visible > Ultraviolet > X-rays > Gamma rays. Thus it is clear that the radio-waves are having the maximum wavelength while the Gamma rays are having minimum wavelength.
Q6. A radio station broadcast at 30 metre band. The frequency of the carrier wave transmitted by this station is:-
एक रेडियो स्टेशन 30 मीटर बैंड पर प्रसारण करता है. इस स्टेशन द्वारा प्रेषित वाहक तरंग की आवृत्ति कितनी होती है:-
(a) 10 KHz /10 किलोहर्ट्ज
(b) 100 KHz / 100 किलोहर्ट्ज
(c) 10 MHz /10 मेगाहट्र्ज
(d) 100 MHz/ 100 मेगाहट्र्ज
Show Answer
S6. Ans.(c)
Sol. According to formula = > n = c/I
[where n=frequency,c=speed of light;I=wavelength]
=(3×〖10〗^8)/30=10×〖10〗^6=10 MHz
Sol. According to formula = > n = c/I
[where n=frequency,c=speed of light;I=wavelength]
=(3×〖10〗^8)/30=10×〖10〗^6=10 MHz
Q7. A cut diamond shines brilliantly due to-
तरासा गया हीरे किसके कारण अत्यधिक चमकता है?
(a) Total internal reflection /पूर्ण आंतरिक परावर्तन
(b) Absorption of light /प्रकाश के अवशोषण
(c) Some inherent property /कुछ अंतर्निहित गुण
(d) Its molecular structure/इसकी आणविक संरचना
Show Answer
S7. Ans.(a)
Sol. The refractive index of diamond is very high. Diamond achieves brilliance partially from total internal refraction. It has been cut or designed in such a way that if light enters into it, incident light strikes many of the internal surfaces.
Sol. The refractive index of diamond is very high. Diamond achieves brilliance partially from total internal refraction. It has been cut or designed in such a way that if light enters into it, incident light strikes many of the internal surfaces.
Q8. The clouds float in the atmosphere because of their low :
बादल वायु-मंडल में उनके कम __________के कारण उड़ते है:
(a) Temperature/तापमान
(b) Velocity/वेग
(c) Pressure/दाब
(d) Density/घनत्व
Show Answer
S8. Ans.(d)
Sol. Clouds from when the invisible water vapour in the air condenses into visible water droplets. They are so small that the effect of gravity on them is negligible. Thus the clouds float in the atmosphere because of their low density.
Sol. Clouds from when the invisible water vapour in the air condenses into visible water droplets. They are so small that the effect of gravity on them is negligible. Thus the clouds float in the atmosphere because of their low density.
Q9. Who discovered Television?
टेलीविजन की खोज किसने की थी?
(a) Edison O/एडीसन O
(b) Galileo/गैलीलियो
(c) Baird/बेयर्ड
(d) Franklin/फ्रेंकलिन
Show Answer
S9. Ans.(c)
Sol. Television was invented by J.L. Baird in 1926 in Britain. Galileo invented the Telescope.
Sol. Television was invented by J.L. Baird in 1926 in Britain. Galileo invented the Telescope.
Q10. In cold countries, alcohol is preferred to mercury as a thermometric liquid because:
ठंडे देशों में, थर्मोमेट्रिक तरल के रूप में अल्कोहल को पारा से अधिक वरीयता दी जाती है क्योंकि:
(a) Alcohol has a lower freezing point /अल्कोहल का हिमांक बिंदु कम है
(b) Alcohol is a better conductor of heat /अल्कोहल उष्मा का एक अच्छा संचालक है
(c) Alcohol is cheaper than mercury /अल्कोहल पारे से सस्ता है
(d) The world production of alcohol is greater than that of mercury /अल्कोहल का विश्व उत्पादन पारा की तुलना में अधिक है
Show Answer
S10. Ans.(a)
Sol. There are lots of reasons for using alcohol than mercury as thermometric liquids. Some alcohol has a very low freezing point of about-112°C and therefore is suitable to record very low temperature.
Sol. There are lots of reasons for using alcohol than mercury as thermometric liquids. Some alcohol has a very low freezing point of about-112°C and therefore is suitable to record very low temperature.
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