Describe the ideas behind the Tonkin Free School. To what extent was it a typical example of colonial ideas in Vietnam ? [CBSE 2009 (F), 2013 (O)]
[question] Question. Describe the ideas behind the Tonkin Free School. To what extent was it a typical example of colonial ideas in Vietnam ? [CBSE 2009 (F), 2013 (O)] [solution] Solution: Ideas behind Tonkin Schools : 1. Spread of Western-style Education : These schools were started in 1907 to provide a Western-style education. This education included classes in science, hygiene and French (these classes were held in the evening and had to be paid for separately). 2. To consolidate their power ...
Read More →The values of current,
[question] Question. The values of current, I, flowing in a given resistor for the corresponding values of potential difference, $V$, across the resistor are given below : I (ampere): $\quad 0.5 \quad 1.0 \quad 2.0 \quad 3.0 \quad 4.0$ $\begin{array}{lllllll}\text { V (volt) } & : & 1.6 & 3.4 & 6.7 & 10.2 & 13.2\end{array}$ Plot a graph between $\mathrm{V}$ and $\mathrm{I}$ and calculate the resistance of the resistor. [/question] [solution] solution: The V-I graph is as shown in fig. Here, the ...
Read More →A stone is allowed to fall from the top of a tower 100 m high
[question] Question. A stone is allowed to fall from the top of a tower 100 m high and at the same time another stoneis projected vertically upwards from the ground with a velocity of 25 ms–1. Calculate when and where the two stones will meet. (Take g = 10 m/s2) [/question] [solution] Solution: For stone moving downward, acceleration due to gravity, $\mathrm{g}=10 \mathrm{~ms}^{-2}$ initial velocity (u) = 0 ; distance, s = 100 – x ; time, t = ? $\mathrm{s}=\mathrm{ut}+\frac{1}{2} \mathrm{gt}^{2}...
Read More →It is often said that the world is witnessing now a second industrial revolution, which will transform the society as radically as did the first.
[question] Question It is often said that the world is witnessing now a second industrial revolution, which will transform the society as radically as did the first. List some key contemporary areas of science and technology, which are responsible for this revolution. [/question] [solution] Solution Solution: Some of the key contemporary areas of technology and science that are now mainly responsible for a new industrial revolution and are likely to occur in the near future are: (1) Design of Su...
Read More →A copper wire has a diameter of 0.5 mm
[question] Question. A copper wire has a diameter of $0.5 \mathrm{~mm}$ and a resistivity of $1.6 \times 10^{-6} \mathrm{ohm} \mathrm{cm}$. How much of this wire would be required to make a 10 ohm coil? How much does the resistance change if the diameter is doubled? [/question] [solution] solution: We are given that, diameter of the wire, $D=0.5 \mathrm{~mm}=0.5 \times 10^{-3} \mathrm{~m}$ Radius $\mathrm{r}=\frac{\mathrm{D}}{2}=\frac{0.5 \times 10^{-3}}{2}=2.5 \times 10^{-4} \mathrm{~m}$ Resist...
Read More →How is voltmeter connected in the circuit
[question] Question. How is voltmeter connected in the circuit to measure potential difference between two points? [/question] [solution] solution: A voltmeter is always connected in parallel across the points between which the potential difference is to be determined. [/solution]...
Read More →Two conducting wires of the same material
[question] Question. Two conducting wires of the same material and of equal lengths and equal diameters are first connected in series and then in parallel in an electric circuit. The ratio of the heat produced in series and parallel combinations would be (1) 1 : 2 (2) 2 : 1 (3) 1 : 4 (4) 4 : 1 [/question] [solution] solution: Since both the wires are made of the same material and have equal lengths and equal diameters, they have the same resistance. Let it be R. When connected in series, their e...
Read More →Explain the following – (a) Only one-third of the students in Vietnam would pass the school-leaving examinations
[question] Question. Q.2. Explain the following – (a) Only one-third of the students in Vietnam would pass the school-leaving examinations. (b) The French began building canals and draining lands in the Mekong delta. (c) The government made the Saigon Native Girls School take back the students it had expelled. [CBSE 2014(D)] Or Why did a major protest erupt in 1926 in the Saigon Native Girls School in Vietnam ? Explain. [CBSE 2014] Or Describe the incident that took place in 1926 in Saigon Nativ...
Read More →Calculate the force of gravitation between the earth and the Sun,
[question] Question. Calculate the force of gravitation between the earth and the Sun, given that the mass of the earth $=6 \times 10^{24} \mathrm{~kg}$ and of the Sun $=2 \times 10^{30} \mathrm{~kg}$. The average distance between the two is $1.5 \times 10^{11} \mathrm{~m}$. [/question] [solution] Solution: Given mass of earth, $\mathrm{M}_{\mathrm{e}}=6 \times 10^{24} \mathrm{~kg} ;$ mass of Sun, $\mathrm{M}_{\mathrm{s}}=2 \times 10^{30} \mathrm{~kg} ;$ distance between them, $\mathrm{r}=1.5 \t...
Read More →A stone is thrown vertically upward with an initial velocity of 40 ms–1. Taking g = 10 ms–2,
[question] Question. A stone is thrown vertically upward with an initial velocity of 40 ms–1. Taking g = 10 ms–2, find the maximum height reached by the stone. What is the net displacement and the total distance covered by the stone ? [/question] [solution] Solution: Initial velocity of stone $\mathrm{u}=40 \mathrm{~ms}^{-1}$ final velocity of stone v = 0 ; acceleration due to gravity $g=-10 \mathrm{~ms}^{2}$ [For upward direction g is taken –ve] ; height attained by stone (h) = ? We, know, $\ma...
Read More →An electric bulb is rated 220 V and 100 W
[question] Question. An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, the power consumed will be: (1) 100 W (2) 75 W (3) 50 W (4) 25 W [/question] [solution] solution: Resistance of the electric bulbs, $R=\frac{V^{2}}{P}$\ $\left(P=\frac{V^{2}}{R}\right)$ or $\mathrm{R}=\frac{(220)^{2}}{100}=484 \Omega$ Power consumed by the bulb when it is operated at 110 V is given by $\mathrm{P}^{\prime}=\frac{\mathrm{V}^{2}}{\mathrm{R}}=\frac{(110)^{2}}{484}=\frac{110 \times 110}{484}...
Read More →Write a note on (a) What was meant by the ‘civilizing mission’ of the colonisers?
[question] Question. Write a note on (a) What was meant by the ‘civilizing mission’ of the colonisers? (b) Huynh Phu So. [solution] Solution: (a) Unlike other colonisers, the French colonisers did not aim only for economic exploitation of their colonies. The French colonising mission was also driven by the idea of a ‘civilising mission’. Just as the British had done in India, the French claimed that they would introduce modern, civilised life to the Vietnamese. The French believed that like all ...
Read More →Which of the following terms does not represent electrical power in a circuit ?
[question] Question. Which of the following terms does not represent electrical power in a circuit ? (1) $I^{2} R$ (2) $\mathrm{IR}^{2}$ (3) VI (4) $\mathrm{V}^{2} / \mathrm{R}$ [/question] [solution] solution: Electrical power, $\mathrm{P}=\mathrm{VI}=(\mathrm{IR}) \mathrm{I}=\mathrm{I}^{2} \mathrm{R}$ $\mathrm{P}=\mathrm{V} \mathrm{I}=\mathrm{V}\left(\frac{\mathrm{V}}{\mathrm{R}}\right)=\frac{\mathrm{V}^{2}}{\mathrm{R}}$ Obviously, $\mathrm{IR}^{2}$ does not represent electrical power in a cir...
Read More →A stone is released from the top of a tower of height 19.6 m.
[question] Question. A stone is released from the top of a tower of height 19.6 m. Calculate its final velocity just before touching the ground. [/question] [solution] Solution: Initial velocity of stone, $\mathrm{u}=0 ;$ final velocity of stone, v = ? height, $\mathrm{h}=19.6 \mathrm{~m}$; acceleration due to gravity, $\mathrm{g}=+9.8 \mathrm{~ms}^{-2}$ We know, $v^{2}=u^{2}+2 g h$ $\mathrm{v}^{2}=(0)^{2}+2 \times 9.8 \times 19.6$ or $\mathrm{v}^{2}=19.6 \times 19.6$ $v=\sqrt{19.6 \times 19.6}=...
Read More →A piece of wire of resistance R is cut into five equal parts.
[question] Question. A piece of wire of resistance $R$ is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is $R^{\prime}$, then the ratio $R / R^{\prime}$ is (1) $\frac{1}{25}$ (2) $\frac{1}{5}$ (3) 5 (4) 25 [/question] [solution] solution: Resistance of each one of the five parts $=\frac{\mathrm{R}}{5}$ Resistance of five parts connected in parallel is given by $\frac{1}{\mathrm{R}^{\prime}}=\frac{1}{\mathrm{R} / 5}+\frac{1...
Read More →A ball is thrown vertically upwards with a velocity of 49 ms–1.
[question] Question. A ball is thrown vertically upwards with a velocity of 49 ms–1. Calculate (i) The maximum height to which it rises. (ii) The total time it takes to return to the surface of the earth. [/question] [solution] Solution: (i) Initial velocity of the ball, $\mathrm{u}=49 \mathrm{~ms}^{-1}$ Final velocity of the ball, $\mathrm{v}=0$ Acceleration due to gravity $g=-9.8 \mathrm{~ms}^{-2}$ [In upward direction, $g$ is taken -ve] Height attained by the ball, $\mathrm{s}=$ ? Time for ri...
Read More →An electric motor takes 5 A from a 220 V.
[question] Question. An electric motor takes 5 A from a 220 V. Determine the power and energy consumed in 2 hr. [/question] [solution] solution: Here, current, $\mathrm{I}=5 \mathrm{~A}$; potential difference, $\mathrm{V}=220 \mathrm{~V}$; time, $\mathrm{t}=2 \mathrm{hr}=2 \times 60 \times 60=7200 \mathrm{~s}$ Power, $\mathrm{P}=\mathrm{V} \times \mathrm{I}=220 \times 5=1100 \mathrm{~W}$ Energy consumed, $\mathrm{H}=\mathrm{V} \times \mathrm{I} \times \mathrm{t}=220 \times 5 \times 7200=7.92 \ti...
Read More →What determines the rate at which energy
[question] Question. What determines the rate at which energy is delivered by a current ? [/question] [solution] solution: Electric power determines the rate at which energy is delivered by a current. [/solution]...
Read More →Why did political leaders differ sharply over the question of separate electorates?
[question] Question. Why did political leaders differ sharply over the question of separate electorates? [/question] [solution] Solution: Political leaders differed sharply over the question of separate electorates because of differences in opinion. While those supporting the cause of minorities and the dalits believed that only political empowerment would resolve their social backwardness, others like Gandhiji thought that separate electorates would further slow down the process of their integr...
Read More →Gravitational force on the surface of the Moon is only
[question] Question. Gravitational force on the surface of the Moon is only $\frac{1}{6}$ as strong as gravitational force on the earth. What is the weight in newton of a $10 \mathrm{~kg}$ object on the Moon and on the earth ? [/question] [solution] Solution: Mass of object $(\mathrm{m})=10 \mathrm{~kg}$ Acceleration due to gravity on earth (g) $=9.81 \mathrm{~ms}^{-2}$. Acceleration due to gravity on Moon $\left(g_{\mathrm{m}}\right)=\frac{9.81}{6} \mathrm{~ms}^{-2}$ Weight of the object on the...
Read More →An electric iron of resistance
[question] Question. An electric iron of resistance $20 \Omega$ takes a current of 5 A. Calculate the heat developed in $30 \mathrm{~s} .$ [/question] [solution] solution: Here, resistance, $R=20 \Omega$, current, $I=5 A$, time, $t=30 \mathrm{~s}$. Heat produced, $\mathrm{H}=\mathrm{I}^{2} \mathrm{R} \mathrm{t}=(5)^{2} \times 20 \times 30$ $=1.5 \times 10^{4} \mathrm{~J}$ [/solution]...
Read More →Imagine you are a woman participating in the Civil Disobedience Movement. Explain what the experience meant to your life.
[question] Question. Imagine you are a woman participating in the Civil Disobedience Movement. Explain what the experience meant to your life. [/question] [solution] Solution: A woman participating in the Civil Disobedience Movement—facts—salt manufactured; foreign cloth boycotted; liquor shops picketed; peaceful satyagrahis attacked, including women and children; brutal repression, many women went to jail as well; mostly from high castes and rich families; saw national service as a sacred duty ...
Read More →Why will a sheet of paper fall slower than one that is crumpled into a ball ?
[question] Question. Why will a sheet of paper fall slower than one that is crumpled into a ball ? [/question] [solution] Solution: Sheet crumpled into a ball has small surface area as compared to the similar unfolded sheet. Therefore, unfolded sheet will experience more resistance due to air as compared to the sheet crumpled into a ball, inspite of same force of gravity acting upon them. It is larger resistance of air which slows down the unfolded sheet, and therefore it falls slower as compare...
Read More →Compute the heat generated while transferring
[question] Question. Compute the heat generated while transferring 96000 coulombs of charge in one hour through a potential difference of 50 V. [/question] [solution] solution: Here, charge, $\mathrm{Q}=96000 \mathrm{C} ;$ time, $\mathrm{t}=1 \mathrm{hr}$ potential difference, $\mathrm{V}=50 \mathrm{~V}$. Heat produced, $\mathrm{H}=\mathrm{V} \mathrm{I} \mathrm{t}=\mathrm{V} \times \mathrm{Q} \quad[\because \mathrm{Q}=\mathrm{I} \mathrm{t}]$ $=96000 \mathrm{C} \times 50 \mathrm{~V}=4.8 \times 10...
Read More →Discuss the Salt March to make clear why it was an effective symbol of resistance against colonialism.
[question] Question. Discuss the Salt March to make clear why it was an effective symbol of resistance against colonialism. [/question] [solution] Solution: The Salt March was an effective symbol of resistance against colonialism because it was done in revolt against a commodity—salt, used by the rich and the poor alike. The tax on salt, and the government monopoly over its production was a severely oppressive administrative move. The Salt March was effective also because Gandhiji met a large nu...
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