Daily Science Test 2

The given options are "নিউটন", "ওহম", "হার্টজ", and "ডেসিবেল". Among these options, "ডেসিবেল" is the unit used to measure the intensity of sound. Therefore, "ডেসিবেল" is the correct answer as it represents the unit of sound intensity.

When a string is stretched four times its original length, the tension in the string increases by a factor of four. Therefore, if the length of the string is increased by a factor of four, the tension will also increase by a factor of four. This means that the tension will be doubled.

The given options describe the characteristics of a laser. The first option states that the intensity of laser light is very high, which is a correct characteristic of a laser. The second option states that laser light is extremely bright and intense, which is also a correct characteristic. The third option states that laser light is of a single color, which is also true. However, the fourth option states that laser light is absorbed by water, which is not true. Laser light can pass through water without being absorbed.

The correct answer is "আলোর পূর্ণ অভ্যন্তরীণ প্রতিফলনের সূত্র". This is because the question is asking for the necessary condition for explaining the phenomenon of mirage. The other options, "আলোর প্রতিফলনের সূত্র" and "আলোর প্রতিসরণের সূত্র", are not directly related to the phenomenon of mirage. The option "আলোর প্রতিসরণের সূত্র" refers to the law of reflection of light, and "আলোর প্রতিফলনের সূত্র" refers to the law of refraction of light. Only the option "আলোর পূর্ণ অভ্যন্তরীণ প্রতিফলনের সূত্র" relates to the complete internal reflection of light, which is necessary for the phenomenon of mirage.

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When the humidity of the air increases, the speed of sound also increases. This is because the water vapor in the air molecules helps to transmit sound waves more efficiently, resulting in a higher speed of sound. Therefore, when the humidity increases, the speed of sound increases as well.

The question asks what color will a yellow object appear in green light. When an object is illuminated with light of a certain color, it absorbs all other colors and reflects or transmits the color it appears. In this case, when a yellow object is illuminated with green light, it will absorb the green light and reflect or transmit all other colors. Since black is the absence of color, the object will appear black in green light.

The correct answer is "লাল - হলুদ - সবুজ - হলুদ - লাল". This is the correct order in which the traffic lights turn on in the city streets. The sequence starts with the red light (লাল), followed by the yellow light (হলুদ), then the green light (সবুজ), another yellow light (হলুদ), and finally back to the red light (লাল) again. This is a common traffic light sequence used in many places to control the flow of vehicles and ensure safety on the roads.

The word "অবতল" translates to "concave" in English. A concave mirror is used to observe the inside parts of the nose, ear, and throat, as it helps to focus the light rays and create a magnified image. Therefore, the correct answer is "অবতল" or "concave".

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The question asks how Badu travels, and the options given are "through sound waves", "through echoes", "both", and "none of the above". The correct answer is "both", indicating that Badu travels both through sound waves and through echoes.

When the density of air increases, the speed of sound decreases. This is because the particles of air are closer together in a denser medium, causing the sound waves to travel slower. Therefore, if the density of air increases, the speed of sound decreases, resulting in a decrease in the speed of the sound.

Gamma rays are the most harmful radiation for living organisms. They have the highest energy and can penetrate deep into the body, causing damage to cells and DNA. Alpha and beta rays have lower energy and can be stopped by a sheet of paper or clothing, while gamma rays require thicker shielding such as lead or concrete. Therefore, gamma rays are the most damaging radiation for living organisms.

ছায়া তৈরি হয় যখন আলোর বিভিন্ন কণার পথ পরস্পরের সাথে সংঘটিত হয়। সরলরৈখিক গতি মানে আলো একটি সরল রেখায় চলে এবং ছায়া তৈরি করে। তাই সরলরৈখিক গতি জন্য ছায়া তৈরি হয়।

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হরিৎ বর্ণের অর্থ হলো সবুজ। তাই সবুজ হলো হরিৎ বর্ণ।

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The question is asking which scientist proved that light is a combination of seven colors. The correct answer is "Newton" because he conducted experiments with prisms and showed that white light is made up of a spectrum of colors when it passes through a prism. This discovery led to the understanding of the rainbow and the color spectrum.

The correct answer is "সোজা ও বিবর্ধিত" which means "straight and enlarged" in English. This suggests that convex lenses, which are thicker in the middle and thinner at the edges, are used to create an enlarged image.

The question asks for the speed of sound at room temperature. The correct answer is ৩৪৭ মিটার/সেকেন্ড, which is the approximate speed of sound at room temperature.

The question provides a list of different types of waves, including "লম্বিক তরঙ্গ" (longitudinal waves). The correct answer is "লম্বিক তরঙ্গ" because it is a type of wave mentioned in the given options.

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The question is asking which type of radiation has the highest frequency. Among the given options, "রঞ্জন রশ্মি" (visible light) has the highest frequency compared to "বেতার তরঙ্গ" (radio waves), "অতিবেগুনি রশ্মি" (ultraviolet rays), and "অবলোহিত রশ্মি" (infrared rays). Visible light falls within a specific range of frequencies in the electromagnetic spectrum, and it is known to have a higher frequency than radio waves, ultraviolet rays, and infrared rays.

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The correct answer is "সবগুলো". This is because the question asks for the speed of light in a vacuum, which is a constant value of approximately 3 lakh kilometers per second, 186,000 miles per second, or 30 billion centimeters per second. Therefore, all of the given options are correct representations of the speed of light.