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Q:

When a bottle of perfume is opened in one corner of a room the smell spreads soon throughout the room. This is an example of

A) surface tension	B) capillarity
C) viscosity	D) diffusion

Answer & Explanation Answer: D) diffusion

Explanation:

Diffusion is the spreading - mixing of gases through molecular motion.

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Filed Under: Physics

Q:

A bucket of water is hung from a spring balance. A piece of iron is suspended in the water without touching the sides or touching the bottom of the the bucket. The reading of the spring balance

A) will increase	B) will decrease
C) does not change	D) varies with the increase of depth of the immersion of the iron piece

Answer & Explanation Answer: A) will increase

Explanation:

When the piece of iron is lowered into the water, the water level in the bucket increases. And so the pressure at the bottom of bucket also increases. Thus the total thrust at bottom also increases. Therefore the spring balance reading increases. Thus (a) is correct.

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Filed Under: Physics

Q:

A man stands in a lift which accelerates upwards. The resultant reaction force on the floor of the lift is

A) greater than the weight of the man	B) less than the weight of the man
C) Same as the weight of the man	D) Zero

Answer & Explanation Answer: A) greater than the weight of the man

Explanation:

The weight of the man mg is acting on the floor. As the lift is moving up with an acceleration, say a, the man too in it is having this acceleration. The force producing this acceleration is ma. By Newton's third law, this force will have an equal reaction pressing the floor equal to ma. Therefore the total resultant reaction on the floor is mg+ma = m(g+a) which is mg, the weight of the man. So (a) is correct.

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Q:

Two pipes A and B can fill a tank in 24 hours and $17 \frac{1}{7}$ hours respectively. Harihar opened the pipes A and B to fill an empty tank and some times later he closed the taps A and B , when the tank was supposed to be full. After that it was found that the tank was emptied in 2.5 hours because an outlet pipe "C" connected to the tank was open from the beginning. If Harihar closed the pipe C instead of closing pipes A and B the remaining tank would have been filled in :

A) 2 hours	B) 8 hours
C) 6 hours	D) 4 hours

Answer & Explanation Answer: B) 8 hours

Explanation:

Efficiency of Inlet pipe A = 4.16% $(\frac{100}{24})$

Efficiency of Inlet pipe B = 5.83% $(\frac{100}{17 \frac{1}{7}})$

Therefore, Efficiency of A and B together = 100 %

Now, if the efficiency of outlet pipe be x% then in 10 hours the capacity of tank which will be filled = 10 * (10 - x)

Now, since this amount of water is being emptied by 'C' at x% per hour, then

$\frac{10 x (10 - x)}{x} = 2.5 h r s$

=> x = 8

Therefore, in 10 hours 20% tank is filled only. Hence, the remaining 80% of the capacity will be filled by pipes A and B in 80/10 = 8 hours

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Filed Under: Time and Work
Exam Prep: AIEEE , Bank Exams , CAT
Job Role: Bank Clerk , Bank PO

Q:

There are three boats B1, B2 and B3 working together they carry 60 people in each trip. One day an early morning B1 carried 50 people in few trips alone. When it stopped carrying the passengers B2 and B3 started carrying the people together. It took a total of 10 trips to carry 300 people by B1, B2 and B3. It is known that each day on an average 300 people cross the river using only one of the 3 boats B1, B2 and B3. How many trips it would take to B1, to carry 150 passengers alone?

A) 15	B) 30
C) 25	D) 10

Answer & Explanation Answer: A) 15

Explanation:

Combined efficiency of all the three boats = 60 passenger/trip

Now, consider option(a)

15 trips and 150 passengers means efficiency of B1 = 10 passenger/trip

which means in carrying 50 passengers B1 must has taken 5 trips. So the rest trips equal to 5 (10-5 = 5) in which B2 and B3 together carried remaining 250 (300 - 50 = 250) Passengers.

Therefore the efficiency of B2 and B3 = 250/5 = 50 passenger/trip

Since, the combined efficiency of B1, B2 and B3 is 60. Which is same as given in the first statement hence option(a) is correct.

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Filed Under: Time and Work

Q:

A can do a piece of work in 10 days, B in 15 days. They work together for 5 days, the rest of the work is finished by C in two more days. If they get Rs. 3000 as wages for the whole work, what are the daily wages of A, B and C respectively (in Rs):

A) 200, 250, 300	B) 300, 200, 250
C) 200, 300, 400	D) None of these

Answer & Explanation Answer: B) 300, 200, 250

Explanation:

A's 5 days work = 50%

B's 5 days work = 33.33%

C's 2 days work = 16.66% [100- (50+33.33)]

Ratio of contribution of work of A, B and C = $50 : 33 \frac{1}{3} : 16 \frac{2}{3}$ = 3 : 2 : 1

A's total share = Rs. 1500

B's total share = Rs. 1000

C's total share = Rs. 500

A's one day's earning = Rs.300

B's one day's earning = Rs.200

C's one day's earning = Rs.250

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Filed Under: Time and Work
Exam Prep: CAT , Bank Exams , AIEEE
Job Role: Bank PO , Bank Clerk

Q:

Amit can do a piece of work in 45 days, but Bharath can do the same work in 5 days less, than Amit, when working alone. Amit and Bharath both started the work together but Bharath left after some days and Amit finished the remaining work in 56 days with half of his efficiency but he did the work with Bharath with his complete efficiency. For how many days they had worked together?

A) 6	B) 8
C) 9	D) 12

Answer & Explanation Answer: B) 8

Explanation:

$\begin{matrix} A m i t & B h a r a t \\ N o . o f D a y s & 45 & 40 \\ E f f i c i e n c y & 2.22 P e r c e n t (= \frac{1}{45}) & 2.5 P e r c e n t (= \frac{1}{40}) \end{matrix}$

Amit did the work in 56 days = $56 \times \frac{1}{45 \times 2} = \frac{28}{45}$

Therefore, Rest work 17/45 was done by Amit and Bharath = $\frac{\frac{17}{45}}{\frac{17}{360}}$ = 8 days

( since Amit and Bharath do the work in one day = $\frac{1}{45} + \frac{1}{40} = \frac{17}{360}$ )

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Filed Under: Time and Work
Exam Prep: AIEEE , Bank Exams , CAT
Job Role: Bank Clerk , Bank PO

Q:

A and B runs around a circular track. A beats B by one round or 10 minutes. In this race, they had completed 4 rounds. If the race was only of one round, find the A's time over the course:

A) 8 min	B) 7.5 min
C) 12.5 min	D) 12 min

Answer & Explanation Answer: B) 7.5 min

Explanation:

B runs around the track in 10 min.

i.e , Speed of B = 10 min per round

Therefore, A beats B by 1 round

Time taken by A to complete 4 rounds

= Time taken by B to complete 3 rounds

= 30 min

Therefore, A's speed = 30/4 min per round = 7.5 min per round

Hence, if the race is only of one round A's time over the course = 7 min 30 sec

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Filed Under: Time and Distance
Exam Prep: AIEEE , Bank Exams , CAT
Job Role: Bank Clerk , Bank PO

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