Q1. The magnetic needle always points in _________ direction.
चुंबकीय सुई हमेशा _________ दिशा में इंगित करती है।
(a) East – West / पूर्व - पश्चिम
(b) West – South / पश्चिम - दक्षिण
(c) North – South / उत्तर - दक्षिण
(d) North – East / उत्तर - पूर्व
Q2. What is the source of electrical energy in an artificial satellite?
एक कृत्रिम उपग्रह में विद्युत ऊर्जा का स्रोत क्या है?
(a) Solar cell / सौर सेल
(b) Mini nuclear reactor / लघु परमाणु रिएक्टर
(c) Dynamo / डायनमो
(d) Thermopile / थर्मोपाइल
Q3. The weight of any body is
किसी भी शरीर का वजन होता है-
(a) same at every place on earth’s surface/ पृथ्वी की सतह पर प्रत्येक स्थान पर समान
(b) maximum at poles / ध्रुवों पर अधिकतम
(c) more on equator / भूमध्य रेखा पर अधिक
(d) more on mountains than in planes / विमानों की तुलना में पहाड़ों पर अधिक
Q4. Transformer is used
ट्रांसफार्मर का उपयोग किया जाता है-
(a) for converting AC into DC / एसी को डीसी में परिवर्तित करने के लिए
(b) for coverting DC into AC / डीसी को एसी में परिवर्तित करने के लिए
(c) to step up DC voltages / डीसी वोल्टेज को बढ़ाने के लिए
(d) to step up or step down AC voltages / एसी वॉल्टेज को ऊपर या नीचे ले जाने के लिए
चुंबकीय सुई हमेशा _________ दिशा में इंगित करती है।
(a) East – West / पूर्व - पश्चिम
(b) West – South / पश्चिम - दक्षिण
(c) North – South / उत्तर - दक्षिण
(d) North – East / उत्तर - पूर्व
Show Answer
Ans.(c)
Sol. The magnetic needle always points North-South direction. Where magnetic north points towards geographic south and magnetic south towards geographic north pole.
Sol. The magnetic needle always points North-South direction. Where magnetic north points towards geographic south and magnetic south towards geographic north pole.
Q2. What is the source of electrical energy in an artificial satellite?
एक कृत्रिम उपग्रह में विद्युत ऊर्जा का स्रोत क्या है?
(a) Solar cell / सौर सेल
(b) Mini nuclear reactor / लघु परमाणु रिएक्टर
(c) Dynamo / डायनमो
(d) Thermopile / थर्मोपाइल
Show Answer
Ans.(a)
Sol. Most artificial satellites have solar cell to generate electricity. Batteries store some of this energy for times when the satellite is in the shadow of the earth.
Sol. Most artificial satellites have solar cell to generate electricity. Batteries store some of this energy for times when the satellite is in the shadow of the earth.
Q3. The weight of any body is
किसी भी शरीर का वजन होता है-
(a) same at every place on earth’s surface/ पृथ्वी की सतह पर प्रत्येक स्थान पर समान
(b) maximum at poles / ध्रुवों पर अधिकतम
(c) more on equator / भूमध्य रेखा पर अधिक
(d) more on mountains than in planes / विमानों की तुलना में पहाड़ों पर अधिक
Show Answer
Ans.(b)
Sol. The weight of any body is maximum at poles.
Weight = mass × acceleration due to gravity(g) g_maximum at poles and
g_minimum at equator hence weight is maximum at poles and minimum at equator.
Sol. The weight of any body is maximum at poles.
Weight = mass × acceleration due to gravity(g) g_maximum at poles and
g_minimum at equator hence weight is maximum at poles and minimum at equator.
Q4. Transformer is used
ट्रांसफार्मर का उपयोग किया जाता है-
(a) for converting AC into DC / एसी को डीसी में परिवर्तित करने के लिए
(b) for coverting DC into AC / डीसी को एसी में परिवर्तित करने के लिए
(c) to step up DC voltages / डीसी वोल्टेज को बढ़ाने के लिए
(d) to step up or step down AC voltages / एसी वॉल्टेज को ऊपर या नीचे ले जाने के लिए
Show Answer
Ans.(d)
Sol. A transformer is an electrical device that transfers energy from one circuit to another by magnetic coupling with no moving parts. It comprises of two or more coupled windings, or a single topped winding, and a magnetic core to concentrate magnetic flux. These are used to convert between high and low voltage, to change impedance, and to provide electrical isolation between circuits.
Q5. When a body is taken from the earth to the moon
जब एक पिंड को पृथ्वी से चंद्रमा पर ले जाया जाता है, तो-
(a) its weight increases / इसका वजन बढ़ता है
(b) its weight decreases / इसका वजन घटता है
(c) its weight remains unchanged / इसका वजन अपरिवर्तित रहता है
(d) it becomes completely weightless / यह पूरी तरह से भारहीन हो जाता है
Q6. An iron ball weighing 10 kg on the earth will weigh in space
धरती पर 10 किलो वजनी एक लोहे की गेंद का वजन अंतरिक्ष में होगा-
(a) less than 10 kg /10 किग्रा से कम
(b) more than 10 kg /10 किग्रा से अधिक
(c) exactly 10 kg / ठीक 10 कि.ग्रा
(d) zero / शून्य
Sol. A transformer is an electrical device that transfers energy from one circuit to another by magnetic coupling with no moving parts. It comprises of two or more coupled windings, or a single topped winding, and a magnetic core to concentrate magnetic flux. These are used to convert between high and low voltage, to change impedance, and to provide electrical isolation between circuits.
Q5. When a body is taken from the earth to the moon
जब एक पिंड को पृथ्वी से चंद्रमा पर ले जाया जाता है, तो-
(a) its weight increases / इसका वजन बढ़ता है
(b) its weight decreases / इसका वजन घटता है
(c) its weight remains unchanged / इसका वजन अपरिवर्तित रहता है
(d) it becomes completely weightless / यह पूरी तरह से भारहीन हो जाता है
Show Answer
Ans.(b)
Sol. When a body is taken from the earth to the moon its weight decreases as the value of gravity on the surface of the moon is 1/6th as that of the earth’s surface.
Sol. When a body is taken from the earth to the moon its weight decreases as the value of gravity on the surface of the moon is 1/6th as that of the earth’s surface.
Q6. An iron ball weighing 10 kg on the earth will weigh in space
धरती पर 10 किलो वजनी एक लोहे की गेंद का वजन अंतरिक्ष में होगा-
(a) less than 10 kg /10 किग्रा से कम
(b) more than 10 kg /10 किग्रा से अधिक
(c) exactly 10 kg / ठीक 10 कि.ग्रा
(d) zero / शून्य
Show Answer
Ans.(d)
Sol. An iron ball weighing 10 kg on the earth will weigh in space zero in space body experiences weightlessness as g = 0.
Sol. An iron ball weighing 10 kg on the earth will weigh in space zero in space body experiences weightlessness as g = 0.
Q7. Which of the following is the best conductor of electricity?
निम्नलिखित में से कौन विद्युत का सबसे अच्छा सुचालक है?
(a) Aluminium / एल्युमिनियम
(b) Copper / कॉपर
(c) Silver / रजत
(d) Gold / सोना
Show Answer
Ans.(c)
Sol. Silver is the best conductor of electricity as compared to aluminium, copper and gold.
Sol. Silver is the best conductor of electricity as compared to aluminium, copper and gold.
Q8.Astronauts in space can’t stand at one place, because
अंतरिक्ष में अंतरिक्ष यात्री एक जगह पर खड़ा नहीं हो सकता, क्योंकि-
(a) there is no gravity / वहाँ कोई गुरुत्वाकर्षण नहीं है
(b) viscous forces of the atmosphere are very strong/ वायुमंडल की श्यान बल बहुत मजबूत होता हैं
(c) solar wind expert an upward force/ सौर पवन एक उर्ध्व बल के लिए विशेषज्ञ हैं
(d) atmospheric pressure is very low/ वायुमंडलीय दबाव बहुत कम है
Show Answer
Ans.(a)
Sol. Astronauts in space can’t stand at one place because there is no gravity in space. The farther one gets from Earth, the less the gravitational force is which implies that gravity is absent in space as astronauts are very far from Earth.
Sol. Astronauts in space can’t stand at one place because there is no gravity in space. The farther one gets from Earth, the less the gravitational force is which implies that gravity is absent in space as astronauts are very far from Earth.
Q9. What should be the characteristic of fuse wire?
फ्यूज तार की विशेषता क्या होनी चाहिए?
(a) High melting point, high specific resistance / उच्च गलनांक बिंदु, उच्च विशिष्ट प्रतिरोध
(b) Low melting point, low specific resistance / कम गलनांक बिंदु, कम विशिष्ट प्रतिरोध
(c) High melting point, low specific resistance / उच्च गलनांक बिंदु, कम विशिष्ट प्रतिरोध
(d) Low melting point, high specific resistance/ कम गलनांक बिंदु, उच्च विशिष्ट प्रतिरोध
Show Answer
Ans.Ans.(d)
Sol. A fuse is a safety device consisting of a strip of wire that melts and breaks an electric circuit if the current exceeds the safe value. Characteristics of a fuse wire are that if should have low melting point, high specific resistance, low ohmic losses, should be economical and free from detraction.
Sol. A fuse is a safety device consisting of a strip of wire that melts and breaks an electric circuit if the current exceeds the safe value. Characteristics of a fuse wire are that if should have low melting point, high specific resistance, low ohmic losses, should be economical and free from detraction.
Q10. The heating element of an electric heater should be made with a material, which should have
विद्युत हीटर के उष्मीय तत्व को एक सामग्री के साथ बनाया जाना चाहिए, जिसमें होना चाहिए-
(a) high specific resistance and high melting point / उच्च विशिष्ट प्रतिरोध और उच्च गलनांक बिंदु
(b) high specific resistance and low melting point / उच्च विशिष्ट प्रतिरोध और कम गलनांक बिंदु
(c) low specific resistance and low melting point / कम विशिष्ट प्रतिरोध और कम गलनांक बिंदु
(d) low specific resistance and high melting point / कम विशिष्ट प्रतिरोध और उच्च गलनांक बिंदु
Show Answer
Ans.(a)
Sol. The working of heating elements is based on heating effect of electric current. When a current is passed through a resistance, it produces heat. The required properties in material used for heating elements is high melting point, high specific resistance, high tensile strength, low temperature coefficient of resistance, high ductility. Mostly nichrome wire is used as a heating element because it is very stable even at high temperatures.
Sol. The working of heating elements is based on heating effect of electric current. When a current is passed through a resistance, it produces heat. The required properties in material used for heating elements is high melting point, high specific resistance, high tensile strength, low temperature coefficient of resistance, high ductility. Mostly nichrome wire is used as a heating element because it is very stable even at high temperatures.
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