Answer:
Total internal reflection is going on. The refractive index of water is about 1.3, so sin 90/sin r=1/sinr=1.3. So the fish can only see objects outside the water within about 50 degrees of the vertical
Answer:
Explanation:
mass of displaced oil = 11 x .9
= 9.9 gm
9.9 x 10⁻³ kg
weight of displaced oil = 9.9 x 9.81 x 10⁻³ N
= .097 N .
buoyant force by oil = .097 N
weight of unknown metal = .1 x 9.8
= .98 N .
weight of metal in oil = .98 - .097
= .883 N .
=

The best method to use in prevention of self-demagnetization of a permanent magnet is by use of a keeper. Keepers were also commonly known as amateurs. They help in storing magnets safely, especially those that have low coercivity ( magnets that are extremely susceptible to stray fields).

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Answer:
a. 2.0secs
b. 20.4m
c. 4.0secs
d. 141.2m
e. 40m/s, ∅= -30°
Explanation:
The following Data are giving
Initial speed U=40m/s
angle of elevation,∅=30°
a. the expression for the time to attain the maximum height is expressed as

where g is the acceleration due to gravity, and the value is 9.81m/s if we substitute values we arrive at

b. the expression for the maximum height is expressed as

c. The time to hit the ground is the total time of flight which is twice the time to reach the maximum height ,
Hence T=2t
T=2*2.0
T=4.0secs
d. The range of the projectile is expressed as

e. The landing speed is the same as the initial projected speed but in opposite direction
Hence the landing speed is 40m/s at angle of -30°
The elements fluorine and chlorine can form minerals in the "halide"group
.
Halide refers to the group containing halogens. The halogens turn out to be less responsive as you go down the group. Fluorine, at the highest point of the group, is the most responsive or reactive halogen. It is to a great degree risky, causing serious synthetic consumes on contact with skin.
Halogens also act as bleaching agents.They will evacuate the shade of colors. Chlorine is utilized to bleach wood mash to influence white paper.